The present study is aimed at the isolation, characterization and evaluation of some biological properties of betulin from Entada africana stem bark extract. A dichloromethane soluble portion of the stem bark methanol/acetone (1:1 v/v) extract was subjected to gradient elution using ethyl acetate in hexane (5 -30 %) on an open column. A pure compound was obtained with Rf = 0.61 in hexane/ethyl acetate (8:2 v/v) after repeated washing and recrystallization from methanol and coded Enac1. The pure compound was analyzed using IR, 1 H & 13 C NMR and GC-MS. Clinical isolates of Escherichia coli, Klebsiella pneumoniae, Salmonella typhi and Staphylococcus aureus were used to assess the antibacterial activity of the pure compound while its preliminary Cytotoxicity was evaluated using brine shrimp nauplii. Based on the spectroscopic data obtained and in comparison with literature, the isolated compound was identified as betulin. The minimum inhibitory concentration (MIC) of betulin ranged between 62.50 -250.00 µg/mL for all the four bacterial isolates in the study while its fifty percent lethal concentration (LC50) was 10.00 µg/mL. Significant Cytotoxicity with moderate antibacterial activity was observed. The study therefore justifies the existence of bioactive compounds in the stem bark of Entada africana and its use in traditional medicine.

The phytochemical  investigation of the stem bark extracts of Entada africana led to the isolation and characterization of Stigmasta-7,22-dien-3-ol from the dichloromethane soluble portion of acetone/methanol (1:1v/v) crude extract. The powdered stem bark sample of Entada africana was defatted with hexane and extracted with acetone/methanol (1:1v/v) mixture. The dichloromethane soluble fraction was purified on a low pressure column containing silica gel 60 (60-200 mesh). The purification afforded an isolate coded Enac3 (85 mg) with Rf value of 0.404 in hexane/ethyl acetate (4:1). The isolate was characterized using IR, NMR data and in comparison with literature. Analysis of spectroscopic data and literature comparison suggests Enac3 as stigmasta-7, 22-dien-3-ol. The isolation of stigmasta-7, 22-dien-3-ol from the stem bark of Entada africana suggests the presence of useful bioactive principles which could be exploited for medicinal purposes.

The study was aimed at the in-vitro investigation of the antibacterial activity, antioxidant potential and bioactive compound isolation from ethyl acetate crude fraction of Laggera aurita (L. aurita) Linn. The crude fraction was tested against five gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus mirabilis) and three gram positive bacteria (Staphylococcus aureus, Enterococcus faecalis and Bacillus subtilis) using macro dilution technique. The antioxidant potentials were evaluated using two different but complementary methods namely ferrous ion chelating activity (FICA) and ferric reducing antioxidant potential (FRAP). Phytocompound isolation was carried out on low pressure open column chromatography. The crude fraction displayed moderate to significant activity against all tested bacteria exhibiting both bacteriostatic and bactericidal effects. The crude fraction showed Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) in the range of 62.50-250 µg/mL and 125-1000 µg/mL respectively. The crude fraction was bactericidal to all tested pathogens except E. coli. The fifty percent effective concentration (EC50) of EDTA standard and the ethyl acetate fraction were obtained as 10.87 μg/mL and 25.77 μg/mL respectively. Similarly the FRAP determinations for ascorbic acid and ethyl acetate fraction yielded 153.63 and 134.40 Fe2+ Equivalent per g of fraction indicating 80.06% and 70.61% FRAP units respectively. The isolated phytocompound coded LAE was obtained as a white crystalline solid with melting point of 136‐138°C and Rf of 0.56 in hexane: ethylacetate (6:4). The isolated compound was identified by spectroscopic data analysis from FT-IR, GC-MS, 1D and 2D NMR and in comparison with literature. The compound was identified as stigmasterol. The observed significant antibacterial and antioxidant properties demonstrated by L. aurita in this study validate its widespread use in traditional medicine. Therefore the study had shown that L. aurita contains bioactive principles and may serve as a source for potential antibacterial and oxidative stress therapeutic agents.

Synthetic larvicides have been used to control malarial vector. However, increasing resistance of mosquito larvae to the synthetic larvicides poses great problem in the vector control. Natural control with plant essential oil may serve as an alternative. This study investigates the chemical constituents and larvicidal activity of volatile oil obtained from Solenostemon monostachyusagainst the larvae of Anopheles gambiae. The volatile oils were extracted using hydro-distillation in a Clevenger type apparatus and analyzed using GC-MS. The larvicidal assay was carried out against Anopheles gambiae larvae at concentration range of 12.5- 400 μg/mL. The analysis of the volatile oil showed that the major constituents of the oil were Caryophyllene oxide (21.6%), β-Caryophyllene (19.6%), β-Pinene (9.8%) and Germacrene D (7.3%). Results showed that larval mortality increases with increasing exposure period to the volatile oils from S. monostachyus. The larvicidal activity demonstrated that the mosquito larvae were susceptible to the volatile oil with LC50 of 23.44 μg/mL. The results suggest that S. monostachyus essential oil has potentials for the control of Anopheles gambiae. Therefore the plant may serve as a potential source of raw material for a new and eco-friendly larvicide.

Boerhavia adscendens (B. adscendens) is a medicinal plant with widespread use in folk medicine. The present study was aimed at evaluation of the cytotoxicity and antioxidant activity of the crude ethanol extract of B. adscendens. The cytotoxicity of the extract was determined using brine shrimp lethality assay while its antioxidant activity was assessed using ferric reducing antioxidant potential (FRAP). The study revealed that the B. adscendens extract has moderate cytotoxic effect against the brine shrimp larvae with LC50 of 100 μg/mL relative to K2Cr2O4 standard with LC50 of 0.01 μg/mL. The FRAP determination for B. adscendens extract yielded an IC50 of 34.56 μg/mL while the ascorbic acid standard had IC50 value of 31.25 μg/mL. These results demonstrate that the B. adscendens ethanol extract has moderate cytotoxicity and quite a significant antioxidant activity. Consequently, these findings may partly explain the usefulness of B. adscendens in traditional medicine.