Determination of the Phytochemical Constituents and Antifungal Properties of Annona senegalensis Leaves (African Custard Apple)

Phytochemical screening of Annona senegalensis leaves was carried out in order to identify and to quantify the bioactive compounds that are present in the plant. Methanol extracts and aqueous extracts of the plant leaves were screened for the presence of ten metabolites. The qualitative study indicated the presence of alkaloids, flavonoids, polyphenols, steroids, cardiac glycoside and carbohydrates for both the aqueous extracts and the methanol leaves extract. Tannins and terpenoids were only present in the aqueous extract and saponins were only present in the methanol extract. Anthraquinones were absent in both of the extracts. Quantitative analysis showed the amount of alkaloid that was present in both the leaves extract of Annona senegalensis. Antifungal activities of the methanol extracts and the aqueous extracts of Annona senegalensis were investigated and assessed against cultured Trichoderma spp fungus. The susceptibility of the tested fungus on the extracts was determined by measuring the diameter of the inhibition zones formed around the well. The highest anti-fungal activity was observed in the aqueous extracts of the leaf. This gave an inhibition zone of 14.5mm. The methanol extract of the leaf gave the lowest inhibition zone of 8.3mm. Keywords: Annona senegalensis, bioactive, extracts, metabolites, leaves, phytochemical, antifunga

Isolation and characterization of a fatty acid from the seed extracts of citrullus lanatus (water melon)

A sample of powdered watermelon seeds sample was macerated with ethanol for two weeks using a maceration method. The mixture was stirred using magnetic stirrer, for 24 hours, in order to extract the powders. It was then decanted, filtered and concentrated on a rotavapor (R110) at 40 ºC in order to obtain the crude ethanol extract (F001). The crude ethanol extract was partitioned into aqueous methanol, chloroform, ethyl acetate and acetone in order to obtain F002, F003, F004 and F005 fractions respectively. The methanol fraction indicated strong activity in the antimicrobial test compared to other fractions. Based on these results, the methanol fraction was subjected to activity-guided chromatographic purification targeting the compound responsible for the observed activity. The methanol fraction (10 g) of the extracted seeds of Citrullus lanatus was chromatographed on a silica gel column, using different eluents. This afforded 117 fractions which were combined based on their thin layer chromatography (TLC) pattern. The pooled fraction (-62 – 67-) was further chromatographed in order to obtain the fatty acid. The structure of the compound was characterized – using,- Proton nuclear magnetic resonance (1H NMR), Carbon-13 nuclear magnetic resonance (13C NMR), Distortionless enhancement bypolarization transfer (DEPT), Fourier transform infrared spectroscopy (FTIR) spectroscopic techniques and Mass spectrometry (MS) analysis in order to propose the structure of the compound as a straight chain aliphatic dicarboxylic acid (3-methylnonadec-4,6-diene1,19-dioic acid)