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Original Papers 795

Telemetry as a Tool to Measure Effects of a Root Extract and Its Single Constituents in Mice

Authors Nicholas K. Chow1, Michael Fretz 2, Matthias Hamburger2, Veronika Butterweck1

Affiliations 1 Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USA 2 Institute of Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland

Key words Abstract showed a mild short-term sedative effect with re- l" L. ! duced locomotor activity between 66–78 min l" Valeriana officinalis L. is a popular treat- minutes after administration. Paradoxically, an l" linarin ment for mild sleep disorders. Clinical and non- increased activity was observed after 150 min- l" clinical studies found contradictory results for va- utes after gavage. A dose of 1 mg/kg valerenic acid l" l" telemetry lerian extracts and single constituents regarding produced an intermittent stimulation of activity. the influence on sleep parameters. It was the aim However, a mild short-term sedative effect was of this study to investigate the sedative effects of a found for linarin at 12 mg/kg and apigenin at valerian root extract. Therefore, locomotor activ- 1.5 mg/kg. Considering the cumulative locomotor ity and core body temperature were recorded in activity over the observation period of 180 min, it male mice using radiotelemetry. A 70% ethanolic is concluded that neither the extract nor one of extract prepared from the roots of V. officinalis the compounds had considerable sedative effects. (s.l.) and some of its single constituents, valerenic More precisely, the observed short-term changes acid, linarin, and apigenin, were tested for effects in activity pattern indicate that valerian extract on locomotion and body temperature over 180 as well as the linarin and apigenin are minutes after oral administration. The extract rather effective to reduce sleep latency than to act was tested in a dose range of 250–1000 mg/kg, as a sleep-maintaining agent. and only a dose of 1000 mg/kg valerian extract Downloaded by: University of Florida. Copyrighted material. Introduction sleep-inducing and sleep-promoting effects are ! contradictory [2–7]. Although sedative and anx- An estimated 10 to 15% of the adult population iolytic effects have been observed in nonclinical received Sept. 8, 2010 revised Nov. 3, 2010 suffers from chronic (≥ 1 month) and studies [8,9], literature provides insufficient evi- accepted Nov. 5, 2010 an additional 25 to 35% from transient or occa- dence to imply beneficial effects on sleep. sional insomnia (< 1 month) [1]. These high prev- Several compounds have been isolated and iden- Bibliography DOI http://dx.doi.org/ alence rates connected with pharmacological tified from valerian root preparations, but it is 10.1055/s-0030-1250589 treatments cause significant economic and clini- still unclear which of them are responsible for Published online December 10, cal costs. Traditionally, preparations obtained the recorded activities. Some of the active com- 2010 from the roots of Valeriana officinalis L. (Valeria- pounds found in commonly used extracts are the Planta Med 2011; 77: 795–803 naceae) are used as an herbal remedy because of sesquiterpenic acids, especially valerenic acid, © Georg Thieme Verlag KG Stuttgart · New York · their putative sleep promoting effects. In most which was recently identified as a GABAA recep- ISSN 0032‑0943 countries, valerian preparations are a marketed tor modulator [8,10]. Recently, sedative or sleep- over-the-counter product with remarkable suc- enhancing properties were detected for the fla- Correspondence Dr. Veronika Butterweck cess. One reason for this is that herbal products vonoids: linarin (acacetin-7-O-rutinoside) [11], Department of Pharmaceutics and dietary supplements are often considered as 6-methylapigenin (4′,5,7-trihydroxy-6-methyl- College of Pharmacy more natural and safer than prescription or other flavone) [12,13], and hesperidin (2S(−)-7-rham- University of Florida PO Box 100494 nonprescription drugs and therefore are very noglucosyl-hesperetin) [12]. More recently, lig- Gainesville FL 32610 popular [2]. nan derivatives, in particular 4′-O-beta-D-gluco- USA Not only are extracts from Valeriana officinalis syl-9-O-(6′′-deoxysaccharosyl)olivil found in V. Phone: + 13522737859 Fax: + 135 22737854 L. the best known, but also the most studied herb- officinalis, were shown to bind the A1 [email protected] al treatment for insomnia. Clinical studies of its , which is linked to [14].

Chow NK et al. Telemetry as a… Planta Med 2011; 77: 795–803 796 Original Papers

In animal studies, sleep parameters are optimally evaluated 10 mL/kg in the following concentrations: 5 mg/kg, under familiar and undisturbed conditions where usual routine 5 mg/kg, 5 mg/kg, valerian extract 250– is not interrupted. Therefore, the measurement of sleep-inducing 1000 mg/kg, valerenic acid 0.5–5.0 mg/kg, linarin 2.0–12 mg/kg, effects in nonclinical studies is complicated by handling-related and apigenin 1.5–6.0 mg/kg. The concentration of each com- disturbances or unfamiliar measuring instruments. For this rea- pound was chosen based on published literature. Control animals son, changes in locomotor activity are used as a surrogate param- only received vehicle of the same volume. eter to quantify the effect of valerian root, and experiments are conducted with methods such as open field [15], rotarod test Animals [16], and elevated plus maze [8,9]. But these approaches require Non-fasted male C57BL/6J mice (supplied by Harlan Sprague special apparatuses, equipped with a particular measuring sys- Dawley, Inc.) weighing 22–30 g (between 8–12 weeks old) were tem (e.g., photocells and detectors, infrared beams and sensors, singly caged in a temperature controlled (20 ± 2°C) quiet room electromagnetic field, or video cameras). Moreover, long-term and maintained on a nonreversed 12-h light/dark cycle (lights studies in animals are not possible using these methods, and on at 6 a. m. and lights off at 6 p.m.). The animals had unlimited therefore results are inadequate for the investigation of sleep-in- access to food (Harlan Teklad LM-485, standard diet) and water. ducing effects (plus handling effects which cause stress). Sleep- From the day of the E-Mitter implantation, all mice were handled wake cycle and body temperature are strongly influenced by daily before the treatment in order to reduce potential handling each other [17]. While core temperature in humans is rapidly ris- stress. Each mouse was considered available for experimental ing in the morning and falling in the evening, activity and body runs after a minimum of 7 days post-transmitter implantation. temperature in mice are subject to an inversed . Animals were randomly assigned to the different treatment It is known that individuals normally fall asleep when core body groups (n = 8 per group). Experiments were conducted between temperature is decreasing [18]. Thus, it is indicated to consult 9 a. m. and 1 p. m. All animal experiments were performed ac- both, activity and core temperature, to evaluate possible effects cording to the policies and guidelines of the Institutional Animal on sleep. Care and Use Committee (IACUC) of the University of Florida, The present study represents an innovative, objective approach Gainesville, USA (NIH publication #85-23), study protocol # to measure sedative effects with minimized handling-related 200801768 (approved on 09/25/2008). stress and remote data collection. The animals can be left undis- turbed during the recording period and long-term data acquisi- G2 E-Mitter implantation tion is possible. Most importantly, effects on locomotion can di- The surgical implantation of the G2 E-Mitters was performed rectly be quantified. For the first time, radiotelemetry was used under aseptic conditions according to the University of Florida, to investigate a 70% ethanolic extract of Valeriana officinalis L. in Animal Care Services Guidelines for Telemetry Implants and mice. Additionally, selected constituents with reported positive Guidelines for Survival Surgery in Mice. Before surgery, meloxicam pharmacological activity, namely valerenic acid, linarin, and api- (Sigma-Aldrich, Inc.) 1 mg/kg was administered orally for analge- genin [8,10, 11,19], were tested. Locomotor activity and body sia, and anesthesia was maintained by 1–3% delivered temperature were recorded and analyzed for possible acute and by nose cone. Twenty-four hours before implantation, the E-Mit- medium-term sedative effects. ters were sterilized with 2.4% activated glutaraldehyde (Cidex®, Johnson & Johnson, Inc.). The abdomen was opened by making a 2-cm incision along the linea alba. The intestines and colon were Material and Methods gently reflected to allow insertion of the E-Mitter into the ab- ! dominal cavity along the sagittal plane, placing it in front of the Extract and single compounds caudal arteries and veins, but dorsal to the digestive organs. The Downloaded by: University of Florida. Copyrighted material. Valerian extract was manufactured by Finzelberg GmbH & Co. positioning is important to acquire accurate temperature data. In KG, with 70% as the solvent and a drug:extract ratio order to prevent migration of the E-Mitter within the peritoneal (DER) of 3–6:1 (91% native extract, batch #: 08016674). Its con- cavity, transmitters were anchored to the abdominal cavity wall tent of sesquiterpenic acids, calculated as valerenic acid, was by the silastic suture sleeve. The peritoneal incision was closed 0.32% (w/w). Valerenic acid (purity ≥ 98.5%) was purchased from using 4/0 caliber monofilament polypropylene nonabsorbable Phytolab GmbH & Co. Linarin (purity ≥ 98.5%) and apigenin (pu- sutures with reverse cutting needle in a simple interrupted stitch rity ≥ 99%) were purchased from Indofine Chemical Company, pattern. The skin incision was closed with a series of 9-mm surgi- Inc. cal staples which were removed 7 days after surgery. Rehydration at the end of the surgery was assured by subcutaneous adminis- Chemicals and drugs tration of sterile isotonic saline (10 mL/kg body weight). Wound Midazolam hydrochloride 50 mg/10 mL solution was purchased recovery was checked regularly. from Bedford Laboratories™. Zolpidem tablets (5 mg) were pur- chased from Henry Schein, Inc. and comminuted by mortar and Telemetry system pestle for preparation as a suspension for oral administration. A data acquisition system, the VitalView® from Mini Mitter, a Caffeine (purity ≥ 99%) was purchased from Sigma-Aldrich, Inc. Respironics Company (Series 4000), was used to acquire animal body temperature and activity data. VitalView® is a software Drug preparation and hardware system specially designed for controlling data col- All preparations for administration were made on the morning of lection in laboratory monitoring of physiological parameters the experimental run. Compounds for oral administration were without the need for animal handling and prior habituation to dissolved, suspended or diluted in a vehicle of deionized water the test environment or the presence of the experimenter. E-Mit- containing 0.5% propylene glycol (Fisher Scientific, Inc.). Com- ters capture energy from the field of radio waves emitted by coils pounds were administered by feeding needle in a volume of of the ER-4000 Energizer/Receiver, allowing the E-Mitter devices

Chow NK et al. Telemetry as a… Planta Med 2011; 77: 795–803 Original Papers 797

Fig. 1 Changes in locomotor activity (A,C,E) and in body temperature (B,D,F) after oral administra- tion of midazolam (5 mg/kg), zolpidem (5 mg/kg), caffeine (5 mg/kg), or vehicle. Values are expressed as mean ± SEM, n = 8 per group. Zero min repre- sents time of dosing. Downloaded by: University of Florida. Copyrighted material. to be free from battery requirements. The signal returned to the Statistical analysis receiver consists of sequences of pulses whose period is depen- All statistical procedures were calculated with GraphPad Prism® dent on temperature. The VitalView® system records the average statistical software package, version 5.00 (GraphPad Software, rate and the receiver converts this pulse frequency into a serial Inc). Locomotor activity and body temperature data were col- bit stream using calibration values specific to each device. For lected in 6-minute intervals and are displayed as mean ± SEM. the quantification of locomotor activity, movement of the im- Comparative cumulative locomotor activity between groups was planted E-Mitter results in fluctuations in signal strength, which analyzed using two-way analysis of variance (ANOVA) followed are detected by the ER-4000 Receiver via telemetry and noted as by Bonferroniʼs post hoc test. Additionally, temperature and ac- activity counts. The total number of these counts during a sam- tivity pattern differences between control and each treatment pling period interval is recorded. After a minimum 5-day wash- group were evaluated using the unpaired two-tailed t-test. A out period following administration of the test substance, each probability level of p < 0.05 was set as statistically significant. mouse was administered its matched control vehicle for a com- parison run. At least two corresponding control values were matched with every test value. On the day of the experiment, Results the cages were placed on the receivers at least one hour before ! dosing. At 9:29 a. m. EST, dosing was started for the first four mice l" Fig. 1A shows the effect of midazolam (5 mg/kg, and at 9:35 a.m. EST for the second four mice. To assure and con- p.o.) and illustrates the rapid onset of action within the first min- trol constant environmental conditions, experiment runs were utes. Locomotor activity was significantly lower at 12 minutes always accompanied by control animals. (control: 104.86 ± 16.48, midazolam: 17.36 ± 4.55; p < 0.001, two-way ANOVA) and 18 minutes (control: 109.45 ± 20.85, mid- azolam: 24.73 ± 11.33; p < 0.001, two-way ANOVA) after adminis- tration. As shown in l" Fig. 1B, body temperature showed a sig-

Chow NK et al. Telemetry as a… Planta Med 2011; 77: 795–803 798 Original Papers

nificant drop of 0.78 °C 12 minutes after dosing (control: 37.19 ± Treatment Group Cumulative activity Table 1 Cu- 0.15 °C, midazolam: 36.41 ± 0.18 °C; p < 0.05, two-way ANOVA). [0–180 min] mulative loco- The mean body temperature for the initial 30 minutes was signif- Control 1242 ± 73 motor activity icantly lower in the midazolam group compared to vehicle (con- Caffeine 5 mg/kg 1622 ± 97* after oral ad- trol: 37.13 ± 0.09 °C, midazolam: 36.66 ± 0.12 °C; p < 0.05, un- Midazolam 5 mg/kg 829 ± 66** ministration of paired two-tailed t-test). Zolpidem 5 mg/kg 951 ± 87* test com- Similarly to midazolam, zolpidem (5 mg/kg, p.o.) decreased the Control 1286 ± 75 pounds. activity in the first 30 minutes (l" Fig. 1C). Mean body tempera- Valerian extract 250 mg/kg 1305 ± 112 ture at 12 minutes after administration was significantly lower Valerian extract 500 mg/kg 1398 ± 158 in the zolpidem group (35.96 ± 0.13°C) than in the control group Valerian extract 1000 mg/kg 1367 ± 108 (36.43 ± 0.07 °C; p < 0.01, unpaired two-tailed t-test) (l" Fig. 1D). Control 1405 ± 97 The total activity for 180 minutes after administration of 5 mg/ Valerenic acid 0.5 mg/kg 1232 ± 175 Valerenic acid 1.0 mg/kg 1221 ± 152 kg caffeine was increased to 126% compared to the control group Valerenic acid 2.0 mg/kg 1268 ± 97 l" ( Fig. 1E). More precisely, locomotion was significantly stimu- Valerenic acid 5.0 mg/kg 1282 ± 171 lated only during the initial 30 minutes with a high significance Control 1303 ± 59 at 12 minutes (control: 72.40 ± 10.86, caffeine: 176.00 ± 31.76; Linarin 2.0 mg/kg 1254 ± 130 p < 0.001), 18 minutes (control: 42.71 ± 10.38, caffeine: 146.43 ± Linarin 6.0 mg/kg 1335 ± 134 36.90; p < 0.001) and 24 minutes (control: 30.09 ± 7.23, caffeine: Linarin 12.0 mg/kg 1197 ± 151 140.29 ± 32.96; p < 0.001) indicating a rapid onset of action. Body Control 1173 ± 73 temperature was not considerably affected (l" Fig. 1F). The cu- Apigenin 1.5 mg/kg 1026 ± 194 mulative locomotor activity of midazolam, zolpidem, and caf- Apigenin 3.0 mg/kg 1185 ± 124 Apigenin 6.0 mg/kg 1195 ± 126 feine are shown in l" Table 1. l" Fig. 2A and C show no major effect on locomotor activity after Values are expressed as mean ± SEM, two-way analysis of variance oral administration of 250 and 500 mg/kg valerian extract, re- (ANOVA) followed by Bonferroniʼs post hoc test, * p < 0.05; ** p < 0.01

Fig. 2 Changes in locomotor activity (A,C,E)and in body temperature (B,D,F) after oral administra- tion of valerian extract (250, 500, and 1000 mg/kg, respectively) or vehicle. Values are expressed as mean ± SEM, n = 8 per group. Zero min represents time of dosing. Downloaded by: University of Florida. Copyrighted material.

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Fig. 3 Changes in locomotor activity (A,C,E, G) and in body temperature (B,D,F,H) after oral ad- ministration of valerenic acid (0.5, 1.0, 2.0, and 5.0 mg/kg, respectively) or vehicle. Values are ex- pressed as mean ± SEM, n = 8 per group. Zero min represents time of dosing. Downloaded by: University of Florida. Copyrighted material.

spectively, and body temperature remained mostly unaffected in tions (2 mg/kg and 5 mg/kg, respectively), valerenic acid did not these concentrations (l" Fig. 2B,D). In a higher concentration of induce any statistically significant changes in locomotion 1000 mg/kg,valerianextractdid not induceasignificantdifference (l" Fig. 3E,G) or body temperature (l" Fig. 3F,H). Overall, valerenic in the overall locomotor activity over 180 minutes (l" Table 1), but acid had no effects on the cumulative activity from 0–180 min altered the pattern of activity with nonsignificant short-term de- (l" Table 1). creases between 60 and 90 minutes (l" Fig. 2E) and increases in l" Fig. 4A and 4B illustrate that linarin at a concentration of 2 mg/ the extract group between 132 and 150 minutes. Body tempera- kg did not considerably affect locomotion or body temperature. ture remained unchanged during the whole recording period ex- After oral administration of 6 mg/kg linarin, a significant increase cept with a nonsignificant increase between 132 and 180 minutes in locomotor activity during the initial 30 minutes compared to (control: 35.68 ± 0.05 °C, extract: 35.96 ± 0.10 °C) (l" Fig. 2F). vehicle was observed. l" Fig. 4C shows the significantly higher ac- No major effects were observed for valerenic acid in a low con- tivity values at 12 minutes (control: 72.40 ± 10.86, linarin: centration (0.5 mg/kg) (l" Fig. 3A,B). One mg/kg of valerenic acid 150.20 ± 35.00; p < 0.05), 18 minutes (control: 42.71 ± 10.38, linar- considerably altered the locomotion pattern (l" Fig. 3C). After a in: 152.80 ± 41.04; p < 0.001) and 24 minutes (control: 30.09 ± prominent increase at 78 minutes, a subsequent decrease oc- 7.23, linarin: 110.80 ± 40.42; p < 0.01). Body temperature was not curred. Between 138 and 180 minutes, activity was significantly affected over the whole observation period (l" Fig. 4B). In a dose lower in the valerenic acid group. Simultaneously, body temper- of 12 mg/kg, linarin significantly reduced locomotor activity be- ature was significantly decreased by 0.34°C during the same pe- tween 60 and 132 minutes (l" Fig. 4E) whereas no effect on body riod (l" Fig. 3D; control: 35.82 ± 0.09°C, valerenic acid: 35.48 ± temperature was observed (l" Fig. 4F). Considering the effects on 0.10 °C; p < 0.05, unpaired two-tailed t-test). In higher concentra-

Chow NK et al. Telemetry as a… Planta Med 2011; 77: 795–803 800 Original Papers

Fig. 4 Changes in locomotor activity (A,C,E)and in body temperature (B,D,F) after oral administra- tion of linarin (2.0, 6.0, and 12.0 mg/kg, respec- tively) or vehicle. Values are expressed as mean ± SEM, n = 8 per group. Zero min represents time of dosing.

the cumulative activity from 0–180 min, linarin had no signifi- gle constituents (valerenic acid, linarin, and apigenin), which are cant effect (l" Table 1). assumed to be mainly responsible for valerianʼs activity. Oral administration of 1.5 mg/kg apigenin induced a significant The outcomes of the positive (midazolam, zolpidem) and nega- reduction in locomotor activity (l" Fig. 5A). The evaluation indi- tive (caffeine) controls are supported by existing literature data Downloaded by: University of Florida. Copyrighted material. cates significantly lower activity between 90 and 120 minutes and validate the used method [23,25–29]. after gavage. The overall activity during 180 minutes did not sig- The effects of valerian root on sleep parameters are only sparsely nificantly differ between the groups after oral administration of investigated in animals. Wagner et al. [30] observed a sedative ac- 3 mg/kg apigenin (l" Fig. 5C). However, locomotion was slightly tion of a fresh valerian tincture at 1000 mg/kg p.o. in mice, lowered between 84 and 114 minutes. Locomotion pattern was whereas an aqueous extract induced a slight decrease in sponta- also not considerably altered after administration of 6 mg/kg api- neous motility at 10 mg/kg p. o. Similar findings are reported by genin (l" Fig. 5E). However, the total cumulative activity re- Leuschner et al. [15] who found pronounced sedative properties mained unaffected (l" Table 1). No considerable effect on body after oral administration of 20 and 200 mg/kg of an aqueous alka- temperature was observed for all concentrations (l" Fig. 5B,D,F). line extract. While assessing these results, it must be taken into consideration that statistical specification or significance is ab- sent in these studies [15,30]. Additionally, enhancing of barbitu- Discussion rate sleeping time is demonstrated in several studies [15,31] and ! considered to be evidence for sedation. But its relevance for prov- It is generally acknowledged that the quality of physiological ing sedative properties remains unclear since have measurements collected from conscious unstressed animals pos- been shown to interfere with CYP P450 [32], and there- sesses the highest validity and best reflects the normal state of fore an increased sleeping time due to interactions of valerian the animal [20–22]. The radiotelemetry system therefore repre- with the metabolism in mice cannot be excluded. sents an adequate method and has proven its justification in Tokunaga et al. [33] reported significant shortening of sleep la- modern pharmaceutical research thanks to a minimum of han- tency in rats after oral administration of 1000 mg/kg valerian ex- dling-related or restraint stress to the animal [17,23,24]. In light tract without affecting total time of wakefulness, non-REM sleep, of the above, the present study was interested in possible seda- and REM sleep. These results are not supported by the present tive effects of a 70% ethanolic valerian extract and some of its sin- study, which did not find any significant effect on total cumula-

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Fig. 5 Changes in locomotor activity (A,C,E)and in body temperature (B,D,F) after oral administra- tion of apigenin (1.5, 3.0, and 6.0 mg/kg, respec- tively) or vehicle. Values are expressed as mean ± SEM, n = 8 per group. Zero min represents time of dosing.

tive activity over 180 minutes. However, 1000 mg/kg altered the between 138 and 180 minutes. These findings are in line with re- activity pattern of the mice and induced a nonsignificant inter- sults from recent studies. Benke et al. [8] reported no indication mittent drop in activity (66–78 min). This short-term depressant for sedative activity for 10 mg/kg p.o. and 30 mg/kg i.p. (elevated effect is not sufficient to ascribe positive effects on sleep, since a plus-maze). A similar conclusion was drawn by Fernandez et al. Downloaded by: University of Florida. Copyrighted material. stimulating activity was observed thereafter. In contrast, 250 mg/ [11]. They observed no in vivo effects in mice at low doses up to kg and 500 mg/kg did not affect locomotor activity at all. Hatte- 15 mg/kg i.p. (-induced sleeping time and sohl et al. [9] drew a similar conclusion since they reported no ef- holeboard test). In contrast, Hendriks et al. [34] found valerenic fect on locomotion for several valerian extract preparations after acid to decrease motility of mice at a concentration of 50 mg/kg acute and subacute (19 days) oral administration. i.p. and higher. The same authors reported in a later study a de- Temperature data indicate that valerian extract produces a mild crease in rotarod performance in mice (100 mg/kg i.p.) and a dose-dependent hyperthermic effect in higher doses. This find- dose-related increase in -induced sleeping time ing is contradictory to Hendriks et al. [34] who reported a hypo- (50 and 100 mg/kg i.p.) [16]. Furthermore, a significant decrease thermic effect for the of V. officinalis and several con- of rectal temperature in mice at concentrations of 100, 200, and stituents, including valerenic acid. In contrast, Hiller and Zetler 400 mg/kg was observed. Paradoxically, after administration of [31] did not observe any influence on body temperature after ad- 50 mg/kg, a mild increase in body temperature occurred [16]. ministration of 50 and 100 mg/kg ethanolic valerian extract (i.p.), Overall, the authors concluded that this compound has central whereas produced a significant hypothermic effect. No depressant properties. However, considering the extremely high marked effects on temperature have been observed in the and unphysiological doses, the relevance of these results has to present study. In conclusion, considering our results on locomo- be questioned. tor activity and body temperature obtained with telemetry, it In the present study, linarin induced only at a higher concentra- seems unlikely that valerian has any significant sedative actions. tion (12 mg/kg) a significant reduction of locomotor activity be- None of the tested concentrations of valerenic acid did signifi- tween 60 and 132 minutes; however, when considering the cu- cantly lower the activity over 180 minutes. However, at a concen- mulative activity, no significant changes were detected. There- tration of 1 mg/kg the activity pattern was considerably altered. fore, the findings of Fernandez et al. [11], could partly be con- A short-lasting increase was observed between 78 and 102 min- firmed. The authors observed depressant effects at doses of 4 utes after administration followed by a reduction in locomotion and 7 mg/kg i.p. in the holeboard test. Furthermore, 7 and

Chow NK et al. Telemetry as a… Planta Med 2011; 77: 795–803 802 Original Papers

14 mg/kg i.p. significantly prolonged the thiopental-induced 5 Diaper A, Hindmarch I. A double-blind, placebo-controlled investiga- sleeping time in mice. Hence it was concluded that linarin pos- tion of the effects of two doses of a valerian preparation on the sleep, cognitive and psychomotor function of sleep-disturbed older adults. sesses sedative and sleep-enhancing activity. In contrast to the Phytother Res 2004; 18: 831–836 findings of Fernandez et al. [11] we found an initial stimulating 6 Leathwood PD, Chauffard F. Aqueous extract of valerian reduces latency effect after oral administration of 6 mg/kg linarin. to fall asleep in man. Planta Med 1985; 4: 144–148 While in the present study all substances were administered or- 7 Taibi DM, Vitiello MV, Barsness S, Elmer GW, Anderson GD, Landis CA. A randomized clinical trial of valerian fails to improve self-reported, ally, Fernandez et al. [11] used intraperitoneal injection. It is polysomnographic, and actigraphic sleep in older women with insom- likely that the different routes of administration caused different nia. Sleep Med 2009; 10: 319–328 effects on locomotor activity. Consequentially, results obtained 8 Benke D, Barberis A, Kopp S, Altmann KH, Schubiger M, Vogt KE, Rudolph using different routes of administration should not be compared U, Möhler H. GABA A receptors as in vivo substrate for the directly. action of valerenic acid, a major constituent of valerian root extracts. Neuropharmacology 2009; 56: 174–181 In the present study, apigenin showed mild sedative effects at 9 Hattesohl M, Feistel B, Sievers H, Lehnfeld R, Hegger M, Winterhoff H. Ex- low concentrations. Locomotor activity was significantly reduced tracts of Valeriana officinalis L. s.l. show anxiolytic and between 90 and 120 minutes (1.5 mg/kg) after gavage. The ob- effects but neither sedative nor myorelaxant properties. Phytomedi- served effect was indeed short-lasting since after 120 minutes ac- cine 2008; 15: 2–15 tivity began to rise to control levels. In higher doses, apigenin did 10 Trauner G, Khom S, Baburin I, Benedek B, Hering S, Kopp B. Modulation of GABAA receptors by valerian extracts is related to the content of valer- not significantly reduce activity or body temperature. Viola et al. enic acid. Planta Med 2008; 74: 19–24 [35] suggested apigenin to act as a partial 11 Fernandez S, Wasowski C, Paladini AC, Marder M. Sedative and sleep- and to possess anxiolytic activity at low doses (3 mg/kg). In the enhancing properties of linarin, a -isolated from Valeriana of- same study, sedative effects were only observed after i.p. admin- ficinalis. Pharmacol Biochem Behav 2004; 77: 399–404 istration of high doses (30 and 100 mg/kg) in mice (holeboard 12 Marder M, Viola H, Wasowski C, Fernandez S, Medina JH, Paladini AC. 6- methylapigenin and hesperidin: new valeriana flavonoids with activ- and locomotor activity test), but not for doses up to 10 mg/kg ity on the CNS. Pharmacol Biochem Behav 2003; 75: 537–545 i.p. Similarly, Avallone et al. [36] reported potent sedative proper- 13 Wasowski C, Marder M, Viola H, Medina JH, Paladini AC. Isolation and ties for high doses (25 and 50 mg/kg i.p.) in rats as well. However, identification of 6-methylapigenin, a competitive for the brain in most of the previously reported studies apigenin was tested for GABA(A) receptors, from Valeriana wallichii. Planta Med 2002; 68: 934–936 anxiolytic properties and not particularly for sedation. 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Chow NK et al. Telemetry as a… Planta Med 2011; 77: 795–803