PHARMACOGNOSTIC AND ANTIOXIDANT STUDIES OF THE PSEUDOBULBS OF EULOPHIA GUINEENSIS LINDL (ORCHIDACEAE)

PHARMACOGNOSTIC AND ANTIOXIDANT STUDIES OF THE PSEUDOBULBS OF EULOPHIA GUINEENSIS LINDL (ORCHIDACEAE)

Abstract:

Eulophia species are cultivated worldwide; it is one of the largest orchid‘s genera in Africa. They are believed to cure many diseases. Eulophia guineensis Lindl (Orchidaceae) is a multipurpose plant, native to West Africa. Traditionally, it is exploited in the treatment of diseases like hypertension, obesity, inflammation, cold by various cultures without scientific evidence. Pharmacognostic studies; microsopical, chemomicroscopic and physicochemical studies were carried out on the pseudobulbs of E. guineensis. The pseudobulbs were extracted with methanol using cold maceration method. Other experiments carried out include preliminary phytochemical screening; in vitro antioxidant studies of the extract and fractions for free radical scavenging properties; Chromatographic analysis of ethyl acetate fraction was evaluated and Infra red analysis was carried out for the isolated compound. Acute toxicity test of the extract on laboratory mice was also investigated using both the intraperitional and oral routes. Microscopical examination revealed the presence of cork cells, epidermal cells, cortex, parenchyma cells, sclerenchyma cells, collenchymas cells, calcium oxalate crystals, mucilage, vascular bundles and fibres. Physicochemical parameters were established for the powdered pseudobulbs, they include moisture content (6.56 %), total ash value (10.83 %), acid insoluble ash (2.5 %), water soluble ash (2.6 %), alcohol extractives (11.50%) and water extractives (24.67 %). E. guineensis pseudobulbs showed significant (p < 0.05) antioxidant activity for methanol extract (IC50 = 44.61 μg/ml), ethyl acetate fraction (IC50 = 7.58 μg/ml) and butanol fraction (IC50 = 1.35 μg/ml) whereas hexane fraction (186.59 μg/ml) and aqueous fraction (IC50 = 1212.47 μg/ml) showed no significant activity on DPPH induced free radical. However, the standard drug ascorbic acid (IC50 = 1.04 μg/ml) performed best. Qualitative phytochemical screening of the viii extract showed the presence of triterpenes, flavonoids, tannins, cardiac glycosides, deoxysugars and carbohydrates. These phyto-constituents were redistributed among the different fractions obtained from the extract. Chromatographic analysis of ethyl acetate fraction resulted in the isolation of a white, crystalline, needle-like compound. Infra red analysis of the compound revealed the presence of hydroxyl, carbonyl, saturated and unsaturated carbons as functional groups. The acute toxicity of the extract showed it to be slightly toxic intraperitionally and practically non-toxic orally with LD50 of 3807.09 mg/kg and greater than 5000 mg/kg body weight respectively. The Antioxidant studies on the pseudobulbs of the plant E. guineensis have scientifically validated the traditional uses of the plant in the treatment of several diseases

PHARMACOGNOSTIC AND ANTIOXIDANT STUDIES OF THE PSEUDOBULBS OF EULOPHIA GUINEENSIS LINDL (ORCHIDACEAE)

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