International Journal of Chemical Studies 2016; 4(5): 80-87 P-ISSN2349–8528 E-ISSN 2321–4902 Novel bioactive triterpenoid saponin from the IJCS 2016; 4(5): 80-87 © 2016 JEZS fruits of Napoleonaea imperialis P. Beauv Received: 11-07-2016 Accepted: 12-08-2016 (Lecythidaceae) Gloria Ihuoma Ndukwe Department of Chemistry, Gloria Ihuoma Ndukwe, Chukwunonye Moses Ojinnaka and Adebola Rivers State University of Omowumi Oyedeji Science and Technology, Nkpolu- Oroworukwo P.M.B. 5080 Port Harcourt, Rivers State, Nigeria Abstract Napoleonaea imperialis P. Beauv (Lecythidaceae) is a medicinal plant commonly found in South-Eastern Chukwunonye Moses Ojinnaka Nigeria. The ripe fruits were extracted and partitioned into hexane, chloroform, n-butanol and aqueous Department of Pure & Industrial fractions. These fractions were earlier tested and shown to possess anti-bacterial activities. The Chemistry, University of Port chloroform extract was chromatographed and purified to give compounds 1-5 whose structures were Harcourt, East/West Road elucidated using ir, 1H and 13C-nmr as methyl-1,3,5-triene-tricyclopentadecanoate (1); 5-methyl-5-toluyl- P.M.B. 5323 Choba, Rivers 3,4,6-trihydropyran-2-one (2, napoleonapyran-2-one); 4-ethoxy-bicyclodecylbenzoate (3); 3β-O-[β-D- State, Nigeria glucopyranosyl(1→2)][β-D-glucopyranosyl(1→4)][β-D-glucopyranosyl]-16α,22α,24,28-tetrahydroxy- 21-β-O-angeloxyolean-12-ene-29-al (4, napoleon aside -B) and 3-O-[β-D-glucopyranosyl]-1,4–dimethyl- Adebola Omowumi Oyedeji 2,4,5,10-tetrahydroxy–bicyclodecane (5). Department of Chemical and Physical Sciences, Walter Sisulu Keywords: Napoleonaea imperialis, Lecythidaceae, fruits, structure, napoleonapyran-2-one, napoleon University, Private Bag X1, aside-B Mthatha 5117 Eastern Cape, South Africa 1. Introduction There are ten species in the genus, Napoleonaea [1], but Napoleonaea imperialis and Napoleonaea vogelli are the most common species found in Southern Nigeria. The bark of Napoleonaea vogelli and Napoleonaea imperialis are used locally as cough medicine. The [2] seed pulp of some species of Napoleonaea is eaten . Different parts of Napoleonaea [3, 4] imperialis P. Beauv are used in traditional medicine for treatment of infectious diseases . The chemistry and pharmacology of different species of Napoleonaea have been reported [5-11]. In our previous studies, the fruits of Napoleonaea imperialis showed great potentials as a molluscicide [12] and anti-bacterial agent [13]. In continuation of our studies, we report the isolation and characterization of novel compounds from the extracts of Napoleonaea [13] imperialis that were earlier shown to be bioactive . 2. Experimental 2.1 General The n-butanol, deuterated chloroform, deuterated methanol and deuterated DMSO used for this work were analytical grade. All other solvents used were re-distilled. The NMR spectra were taken on Bruker 600 MHz and Bruker 400 MHz operating at 600.1 MHz and 400.22 MHz for proton and 150.89 MHz and 100.63 MHz for carbon 13 respectively. NMR of pure compounds were processed using Bruker software. All samples were run at 25 oC. NMR 13 spectra were calibrated using solvent signals ( C : CDCl3 77.23ppm, DMSO-d6(CD3SOCD3) 13 39.51ppm, C : CD3OH 49.2ppm ) or a signal of the proton of the partly or non deuterated 1 1 solvent ( H : CHCl3 in CDCl3 δ7.24ppm, DMSO in DMSO-d6 δ2.50ppm, H : CH3OH in CD3OD -3.31ppm, 4.78ppm) with tetramethylsilane as internal reference. Chemical shifts (δ) are expressed in ppm. Structural elucidation was based on the interpretation of 1H, 13C, DEPT 1 1 1 13 1 13 Correspondence 90°, DEPT 135°, H- H COSY, NOESY, H- C direct correlation (HSQC) and H- C long- Chukwunonye Moses Ojinnaka range correlation (HMBC). Ultra violet (UV) spectra were recorded on Perkin Elmer Lambda Department of Pure & Industrial 25 UV-Visible spectrophotometer. Fourier transform infrared (FT-IR) spectra were recorded Chemistry, University of Port on Perkin Elmer Spectrum FT-IR spectrophotometer. Analytical thin layer chromatography Harcourt, East/West Road (TLC) was carried out on silica gel Merck F precoated plates. Detection was made under P.M.B. 5323 Choba, Rivers 254 State, Nigeria ultraviolet light at wavelength 254nm and by spraying reagent (anisaldehyde − sulphuric acid) ~ 80 ~ International Journal of Chemical Studies followed by heating. Column chromatography (CC) was Fractions 474-485 (120.2mg). On purification with activated performed using silica gel 60H (Merck code TA1443034) as charcoal and alumina, fractions (474-485) afforded compound adsorbent/packing material. Gel filtration was done using 4 (37.5mg), a cream coloured powder. Compound 4 showed sephadex LH-20 (Sigma-Aldrich). Preparative layer one purple spot, Rf 0.25 (CHCl3-MeOH-H2O, 65:35:10, lower chromatography (PLC) was performed using Silica gel GF phase); 0.05 (CHCl3-MeOH-H2O, 70:30:10, lower phase) and F254 (Analtech Uniplate Cat. Number 02012). 0.4 (n-BuOH-AcOH-H2O, 40:10:50, upper phase); mp 219- 221 °C; ir (ʋ, cm-1) 3320 (broad), 2970, 1239, 1034; 1H, 13C- 2.2 Plant Material nmr (Table 4). Fresh ripe fruits of Napoleonaea imperialis were harvested from Obinze in Owerri Capital Territory, Imo State, Nigeria. Fractions 494-504 (89.1mg). The combined fractions (494 – The plant was identified and authenticated by Mr. J. Opayemi, 504) were packed on silica gel column (3g, 40 cm x 1.5 cm) Department of Plant Science & Biotechnology, University of and eluted with CHCl3-MeOH-H2O (70:20:10, lower phase) Port Harcourt and voucher sample, UPH 147, deposited at to obtain fractions 20-66 (43.4mg), which was further purified University of Port Harcourt Herbarium. The seeds were on preparative TLC silica gel and eluted with CHCl3-MeOH- seperated from their rinds and were air-dried, and then H2O, 65:35:10, lower layer to afford a white Compound 5 crushed to coarse powder at room temperature and weighed. (21.4mg). Compound 5 has Rf 0.21 (not visible in UV but green colouration with spray); ir (υ, cm-1), 3300 (broad), 2940 2.3 Extraction and 1030; 1H, 13C-nmr (Table 5). The dried powdered seeds (970g) were exhaustively extracted with n-butanol (1.5 liters) by cold maceration for 48 hours. 3. Results and Discussion The extracts were combined and concentrated to dryness The crushed powdered seeds of N. imperialis were extracted using rotary evaporator to give a dark brown sticky crude with n-butanol and the extract was partitioned into hexane, extract (96.2g). The dark brown sticky crude extract (48g), chloroform, n-butanol and aqueous fractions. The chloroform was fractionated by solvent partitioning method using hexane, extract was chromatographed using various solvents to obtain chloroform-distilled water (8:2) and n-butanol-water (8:2) to compounds 1-5. afford four extracts: hexane extract (9.7g) chloroform extract Compound 1, mp 82-84 °C, had IR absorptions (Fig. 1) at (23.9g), n-butanol extract (6.6g) and the aqueous extract 1735, 1260 1215 cm-1(ester), 1610 cm-1 (C=C). 1H-nmr (Table (7.8g). 1, δ) had 9.64(s, H-1), 7.66(m, H-2), 7.43(m, H-4), 6.45(H-3), 4.7(s, H-16). The 13C NMR spectrum (Table 1 δ) showed 16 2.4 Isolation carbons while its DEPT spectrum revealed the presence of The chloroform extract (5g) was chromatographed on a three carbon singlets at 177.5 (C-15, carbonyl carbon), 167.7 column (80 x 5cm) of silica gel (225g) and eluted and 132.4 (C-10 and successively with, hexane-EtOAc (6:4), 100% ethylacetate, 13 1 and finally CHCl3-MeOH-EtOAc-H2O (15:22:40:10, lower Table 1: NMR ( CNMR 100.63 MHz and HNMR 400.22 MHz in phase). TLC was used to monitor the fractions and detection CDCl3) data for Compound 1 was carried out by spraying with anisaldehyde-H2SO4 spray Position δ 13C δ 1H reagent and heating. A total of 531 fractions of 20ml each 1 30.3(d) 9.64(s) were collected and combined on basis of TLC to afford 33 2 130.8(d) 7.66(m) main fractions. The hexane-EtOAc (6:4) eluent (130mg) was 3 109.9(d) 6.45 purified on a column (45 x 1cm) of silica gel (3.9g) using 4 128.8(d) 7.43(m) hexane-EtOAc (8:2). A total of 203 fractions (1ml each) were 5 132.4(s) - collected, combined and analysed as follows: 6 14.0(t) 0.78 7 10.9(t) 0.80(m) Fractions 72-75 yielded a yellow solid compound 1 (2.8mg); 8 29.6(d) 1.26(m) 9 28.9(d) 1.30 Rf value 0.17 (hexane-EtOAc, 8:2; pink spot under UV light 10 167.7(s) - and purple spot with spray); mp 82-84 °C; uv (λmax, nm) 325; ir (υ, cm-1) 2959, 2800, 1735, 1460, 1260, 900, 800, 730; 1H, 11 68.1(d) 4.13(m) 13C-nmr (Table1). 12 38.7(t) 1.65(m) 13 23.7(t) 1.38(m) 14 22.9(t) 1.25(m) Fractions 80-83 afforded a yellow solid compound 2 15 177.5(s) - (6.4mg); Rf 0.15 (hexane-EtOAc, 8:2; a pink spot under the 16 57.7(q) 4.70(s) UV light and purple spot with spray); mp 79-81 °C, uv (λmax, nm) 326, ir (υ cm-1) 2918, 2849, 1737, 1673, 1521, 1217, 908, 1 13 C-5, two aromatic carbons), seven doublets at 130.8(C-2), 732; H, C-nmr (Table 2). 128.8(C-4), 109.9(C-3), 68.1(C-11), 30.3(C-1), 29.6(C-8), and 28.9(C-9), five tertiary carbons at 38.7(C-12), 23.7(C-13), Fractions 128-179 afforded a white solid compound 3 22.9(C-14), 14.0(C-6), 10.9(C-7) and one quartenary carbon (8.7mg); Rf value 0.13 (hexane-EtOAc, 8:2; grayish-green -1 at 57.7(C-16).