Stachytarpheta jamaicensis (family Verbanaceae) commonly known as blue porterweed is widely used in folk medicine for the treatment of various diseases including diabetes mellitus. The present study investigated the blood glucose lowering effect and the antioxidant activity of the leaf extracts of Stachytarpheta jamaicensis. The phytochemical screening of the powdered leaf sample was done according to standard procedures. The antioxidant activity of the methanol and ethyl acetate extracts of the leaves were investigated using the 1,1-diphenyl-2-picrylhydrazine (DPPH) radical scavenging assay, the total phenolic and flavonoid contents were also evaluated following standard procedures. The hypoglycaemic effect of the extracts was evaluated using streptozotocin-induced diabetes in rats. Phytochemical screening shows the presence of carbohydrates, alkaloids, saponins, tannins, phenolic compounds, and flavonoids. The extracts demonstrated appreciable and concentration-dependent radical scavenging effect with IC50 values of 16.95 µg/mL and 33.12 µg/mL, for the methanol extract and ethyl acetate extract, respectively. Oral administration of the extracts at 200 mg/kg and 400 mg/kg daily dose significant lowers blood glucose levels in streptozotocin-induced diabetes in experimental rats compared to the control group (untreated diabetic animals). The present findings have therefore shown that S. jamaicensis leaves has hypoglycaemic and antioxidant effects and may therefore serve as a potential source of hypoglycaemic agent as well as antioxidant agents for the prevention and management of free radical induced metabolic diseases.

Caesalpinia pulcherrima (Caesalpiniaceae) is an ornamental plant with several ethnomedicinal uses. The present study was designed to investigate the brine shrimp cytotoxicity and insecticidal activity of oil obtained from C. pulcherrima root. The powdered root was extracted with methanol and then defatted with petroleum ether o C) to obtain a viscous oil. The oil was investigated for its brine shrimp cytotoxicity and insecticidal activity in vitro. The chemical constituents were identified by Gas chromatography-Mass spectrometry. The oil showed significant lethal effect against Artemia salina (Brine shrimp) with LC 50 of 23.85 µg/mL and mild insecticidal activity against Tribolium castaneum and Callosbruchus analis with percentage mortality of 20% and 40% respectively at 1 mg/cm 2 . GC-MS analysis identified 37 compounds mainly steroids, terpenoids and fatty acids. © JASEM https://dx.doi.org/10.4314/jasem.v21i2.8

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Malaria is responsible for about a million deaths yearly. The fight against malaria is faced with the occurrence of widespread resistance of the malaria parasite, Plasmodium spp. The search for plant derived anti-malarial drugs has become greatly imperative. This study was aimed to isolate and investigate the In vivo anti-malarial activity of pulcherrimin A isolated from the stem bark of Caesalpinia pulcherrima. Ethyl acetate fraction of the stem bark extract was subjected to fractionation over silica gel column to obtain pure compound which was characterized as 3,5,6,7tetrahydroxy-19-vouacanoic acid;(3β,5α,6β,7β)-form,6,7-dibenzoyl (pulcherrimin A) a known compound using various spectroscopic techniques. Pulcherrimin A was evaluated for In vivo anti-malarial activity against P. berghe infected mice using the 4-day suppressive test. Different doses (50, 200 and 400 mg/kg/day) of pulcherrimin A were administered to the mice after parasite inoculation. A maximum parasitaemia suppression of 68.18% was observed for the middle dose (200 mg/kg/day) in contrast with 40.91% for the highest dose (400 mg/kg/day). The study therefore revealed that pulcherrimin A isolated from the stem bark of C. pulcherrima exhibited moderate-dose significant (p<0.05) inhibition of P. berghei parasite, thus authenticating the local usage of different parts of the plants in the treatment of malaria and other pyrexia-related infections.

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