Abstract

ISOLATION OF BIOACTIVE CONSTITUENTS AND MECHANISMS OF ANTI-INFLAMMATOTRY ACTIVITY FROM SANSEVIERIA LIBERICA GEROME AND LABROY LEAVES (DRACAENACEAE)

Ezea, Charity Chinasa*, Anowi, Fredrick Chinedu, Ifebi, Hope Morris, Ugwu Patience Ngozi, Okafor, Martha Adaobi, Inya-Agha, Stella Ifeoma, Ezugwu,
Christopher Obodike and Diovu and Edith Obioma

ABSTRACT

Introduction: The anti-inflammatory and antioxidant activities of the methanol leaf extract, fractions and isolate of Sansevieria liberica Ger. and Labr. was investigated. The experimental design was adopted in this study. Methodology: Freshleaves of Sansevieria liberica were collected, cut into pieces, dried for five weeks under shade and pulverized. About 2 kg of the powdered leaves was extracted with 5 × 2.5 L of 80 % methanol(in aliquot extraction) for 72 h by cold maceration. The methanol extract (ME) was concentrated in vacuo using rotary evaporator. About 25 g of the ME was subjected to liquidliquid partitioning successively with 2.5 L of n-hexane, ethylacetate, and butanol using separating funnel to give the n-hexane (HF), ethylacetate (EF), butanol (BF) and water (WF) soluble fractions respectively. Phytochemical screening and acute toxicity test of the extract and fractions were done using standard methods. The ME and fractions were screened for anti-inflammatory and antioxidant activities as well as the possible mode of action using standard in vitro and in vivo models. The most active fraction, EF (2 g) was subjected to VLC separation (silica gel 500 g, sintered funnel 5 L) to give 19 sub-fractions (ECF-1 to ECF-19) which were also subjected to bioassays. The most active sub-fraction, ECF-10 was further purified through Sephadex LH-20 (3 × 60 mesh) which yielded 6 bulked sub-fractions. The most active sub-fraction, ECF-10E which was found pure on HPLC analysis was subjected to LC-ESl-MS and NMR (HNMR, 13C NMR, HMBC, DEPT) spectroscopic analysisfor structure elucidation and also screened for antiinflammatory and antioxidant activities. Result: The yield for extract/ fractions were 50.32, 42.24, 10.52, 8.73, 6.35 % for ME, HF, EF, BF and WF respectively. Phytochemical analysis of the ME, fractions and isolate revealed–Saponins, steroids, flavonoids, terpenoids, tannins, glycosides, resins, fats and oil, alkaloids etc. The LD50 of ME was found to be > 5000 mg/kg. The ME, fractions, sub-fractions and isolate showed significant (p < 0.05) anti-inflammatory and antioxidant activities. The potency/activity of the extract andfractions increased in the order: EF >ME >BF >WF >HF, with75.32 %, 55.20 %, 42.39 %, 39.42 %, 32.50 % at 400 mg/kg for egg albumin-induced edema in rats. Effects of the ME and EF on topical edema induced by xylene on mouse ear revealed that EF at 5 mg had the highest activity with percentage inhibition of 75.43 % compared to 70.54 % inhibition produced by indomethacin at 5 mg. EF at 400 mg/kg produced the highest activity in the formaldehyde induced arthritis with percentage inhibition of 68.74 %. Result of the ulcerogenic effect in rats demonstrated that both ME and EF possess ulcerogenic effect though lower than that produced by indomethacin. ME and EF at 400 and 200 mg/kg also produced significant (p < 0.05) inhibition of leucocytes migration compared to indomethacin at 100 mg/kg. Both the ME and EF produced stabilization effect on the heat-induced and hypotonicity-induced red blood cell haemolysis. In both DPPH radical and hydrogen peroxide scavenging tests, EF produced the highest antioxidant activities with EC50 of 29.93 and 18.63 μg/ml respectively. Sub-fraction ECF-10E at 50 μg/ml produced the highest activity on topical edema induced by xylene on mouse earand DPPH radical test with percentage inhibition of 88.54 and 89.45 % compared to 79.65 and 90.46 % inhibition produced by indomethacin and ascorbic acid at 50 and 200 μg/ml respectively. Isolated compound from ECF-10E at 100 and 500 μg/ml produced highest activities on topical edema induced by xylene on mouse earand DPPH radical test with percentage inhibition of 45.68 % and EC50 of 42.03 μg/ml compared to 57.54 % and EC50 of 12.01 μg/ml inhibition produced by diclofenac sodium and ascorbic acid at 100 and 500 μg/ml respectively. Compounds identified through HPLC-DAAD and LCMS analysis are: pavetanin, aplysamine-2, abscisic acid (ABA), and α–conidendirin. The structure of the isolated compound was elucidated as Quercetin-3-O-α-L-arabinofuranoside based on 1D and 2D NMR and mass spectrometry.

Keywords: Medicinal plants, Isolation, Sansevieria liberica, Quercetin-3-O-?-Larabinofuranoside.