plants Communication Ethnobotanical Survey of Dracaena cinnabari and Investigation of the Pharmacognostical Properties, Antifungal and Antioxidant Activity of Its Resin Mohamed Al-Fatimi Department of Pharmacognosy, Faculty of Pharmacy, Aden University, P.O. Box 5411, Maalla, Aden, Yemen; [email protected] Received: 28 September 2018; Accepted: 24 October 2018; Published: 26 October 2018 Abstract: Dracaena cinnabari Balf. f. (Dracaenaceae) is an important plant endemic to Soqotra Island, Yemen. Dragon’s blood (Dam Alakhwin) is the resin that exudes from the plant stem. The ethnobotanical survey was carried out by semi-structured questionnaires and open interviews to document the ethnobotanical data of the plant. According to the collected ethnobotanical data, the resin of D. cinnabari is widely used in the traditional folk medicine in Soqotra for treatment of dermal, dental, eye and gastrointestinal diseases in humans. The resin samples found on the local Yemeni markets were partly or totally substituted by different adulterants. Organoleptic properties, solubility and extractive value were demonstrated as preliminary methods to identify the authentic pure Soqotri resin as well as the adulterants. In addition, the resin extracts and its solution in methanol were investigated for their in vitro antifungal activities against six human pathogenic fungal strains by the agar diffusion method, for antioxidant activities using the DPPH assay and for cytotoxic activity using the neutral red uptake assay. The crude authentic resin dissolves completely in methanol. In comparison with different resin extracts, the methanolic solution of the whole resin showed the strongest biological activities. It showed strong antifungal activity, especially against Microsporum gypseum and Trichophyton mentagrophytes besides antioxidant activities and toxicity against FL-cells. These findings confirm and explain the traditional uses of the resin for the treatment of skin diseases and mouth fungal infections. Keywords: Dracaena cinnabari; ethnobotany; resin; organoleptic; extractive value; antifungal; antioxidant; Soqotra 1. Introduction Dragon’s blood is the English common name which has been applied to the red coloured resins that are obtained from six different plant genera, Dracaena, Daemonorops, Calamus, Pterocarpus, Eucalyptus and Croton [1–3]. Besides Dracaena cinnabari, the genus Dracaena is represented by some other species, e.g., D. ombet and D. serrulata that are distributed in tropical Africa and southwest Arabia and D. draco, D. tamaranae from the Canary Islands and Morocco [4]. D. cinnabari Balf. f. (Dracaenaceae) is endemic to Soqotra Island, Yemen (Figure1), in which more than 308 plant species have been considered to be endemic [4,5]. The resin of D. cinnabari from Soqotra is well known as a traditional remedy with a long history [4]; it has been traded as medicine and as a colourant agent for use in works of art for centuries, e.g., it has been discovered in some art works in a museum in Germany [3]. The original source of dragon’s blood resin is believed to be D. cinnabari from Soqotra [1] (Figure1) but numerous different resins produced from different plant species are available on the international markets under the name of Dragon’s blood [3]. Therefore, some methods have been studied to differentiate these species red resins, e.g., solubility, gas chromatography coupled to mass spectrometry [3], Raman spectroscopy [1,2] Plants 2018, 7, 91; doi:10.3390/plants7040091 www.mdpi.com/journal/plants Plants 2018,, 7,, 91x FOR PEER REVIEW 2 of 13 spectrometry [3], Raman spectroscopy [1,2] and UV spectroscopy. Flavylium chromophores (7,4′- 0 anddihydroxyflavylium) UV spectroscopy. [6], Flavylium have been chromophores identified to (7,4be responsible-dihydroxyflavylium) for the red colour [6], have of beenD. cinnabari identified resin, to bewhile responsible other flavylium for the red derivatives colour of areD. cinnabariresponsibleresin, for while the red other color flavylium of the other derivatives species are resins responsible that are foralso the called red Dragon’s color of the blood other [6]. species The Soqotri resins thatresin are is the also most called famous Dragon’s crude blood drug [ 6used]. The in Soqotrithe traditional resin is themedicine most famousin Soqotra crude Island drug [4,5,7]. used inMoreover, the traditional it is imported medicine from in Soqotra Soqotra Island in order [4,5 to,7 ].be Moreover, used in other it is importedtraditional from medicine Soqotra systems in order all toover be usedthe world, in other espe traditionalcially for medicinethe treatment systems of skin all over diseases the world, [2,4], especiallybeside other for Dragon’s the treatment blood of resins skin that diseases have [ 2been,4],beside reported other in different Dragon’s traditional blood resins medicine that have systems been reportedin the world in different [4,8]. traditional medicine systems in the world [4,8]. Some polyphenolic derivatives suchsuch asas chalcones,chalcones, homoisoflavans,homoisoflavans, flavones,flavones, biflavonoidsbiflavonoids (Cinnabarone),(Cinnabarone), triflavonoidstriflavonoids (Damalachawin) (Damalachawin) and metacyclophanesand metacyclophanes (dracophane) (dracophane) have been have identified been inidentified the resin in oftheD. resin cinnabari of D. cinnabaribesides besides many sterols many sterols such as such campesterol, as campesterol, stigmasterol, stigmasterol, sitosterol sitosterol and stigmastanoland stigmastanol [6,9– [6,9–14].14]. Concerning Concerning its biological its biological activities, activities, antioxidant antioxidant and cytotoxicand cytotoxic properties properties have beenhave reportedbeen reported [7,9,15 ].[7,9,15]. Our previous Our previous study [7 study] reported [7] reported the marked the cytotoxic marked activitycytotoxic of aactivity methanolic of a solutionmethanolic of thesolution resin of ofD. the cinnabari resin ofon D. the cinnabari humanECV-304 on the human cell line ECV-304 (human bladdercell line carcinoma (human bladder cell line withcarcinoma endothelial cell line properties) with endothelial [7]. properties) [7]. In thethe coursecourse of of our our biological biological and and phytochemical phytochemical studies studies of medicinal of medicinal plants plants from Yemen from [Yemen5,7,16], we[5,7,16], investigated we investigated the resin the of D. resin cinnabari. of D. cinnabari.Different ethnobotanicalDifferent ethnobotanical data about dataD. cinnabari about D.have cinnabari been reportedhave been by reported Al-Fatimi by [Al-Fatimi5] and by [5] Miller and [4by]. ThoseMiller are[4]. comparedThose are compared with our ethnobotanical with our ethnobotanical survey in thesurvey present in the study. present The study. aim of The this aim study of wasthis stud to documenty was to thedocument ethnobotanical the ethnobotanical data and the data traditional and the medicinaltraditional and medicinal non-medicinal and non-medicinal uses of the plantuses andof th itse plant resin. and The its pharmacognostical resin. The pharmacognostical and organoleptic and propertiesorganoleptic of properties the D. cinnabari of the D.resin cinnabari weredetermined resin were determined for the first for time thein first this time study. in this These study. findings These canfindings be used can for be theused identification for the identification and quality and control quality of control the resin of inthe case resin of in adulterations. case of adulterations. In addition, In theaddition,in vitro theantifungal in vitro antifungal activity of activity the resin of the against resin some agains humant some pathogenichuman pathogenic fungalstrains fungal andstrains its antioxidantand its antioxidant activity activity have been have investigated been investigated to confirm to confirm the traditional the traditional medicinal medicinal uses. uses. (a) (b) Figure 1.1. TheThe ecological ecological habitat habitat (a) ( anda) and the purethe pure raw resinraw (resinb) of D.(b cinnabari) of D. cinnabariin Soqotra in Island Soqotra (Author’s Island pictures(Author’s 1990). pictures 1990). 2. Results and Discussion 2.1. Ethnobotany of Dracaena cinnabari 2.1. Ethnobotany of Dracaena cinnabari 2.1.1. Botanical Data 2.1.1. Botanical Data Dracaena cinnabari Balf. f. (Dracaenaceae) is the botanical name of an endemic wild tree, growingDracaena on Soqotra cinnabari Island Balf. (Figuref. (Dracaenaceae)1). Dragon’s is the blood botanica is thel name English of an common endemic name wild fortree, both growing tree andon Soqotra resin. The Island Arabic (Figure name 1). “ DamDragon’s Alakhwin blood” meansis the “Brother’sEnglish common blood” name and is for also both used tree for and both resin. tree andThe Arabic its resin name (Figure “Dam1, TableAlakhwin1). In” means contrast, “Brother’s there are blood” two different and is also Soqotri used for names both for tree the and tree its andresin its(Figure resin. 1, The Table local 1). SoqotriIn contrast, name there of the are endemic two different plant (tree)Soqotri is “Ahrrebonames for”, whilethe tree the and Soqotri its resin. name The of thelocal authentic Soqotri name pure superiorof the endemic resin is plant“Emzoloh (tree)”(Figure is “Ahrrebo1, Table”, while1). All the informants Soqotri name (100%) of reportedthe authentic the twopure Soqotri superior local resin names is “Emzoloh of the plant” (Figure and the1, Table resin. 1). Only All 40%informants held knowledge (100%) reported about the the Arabic two Soqotri name “Damlocal