Bioassay guided fractionation, isolation and characterization of hepatotherapeutic 1, 3-di-ortho-galloyl quinic acid from the methanol extract of the leaves of Pterocarpus santalinoides.

ETHNOPHARMACOLOGICAL RELEVANCE: Leaf extracts of Pterocarpus santalinoides DC are traditionally used to ameliorate ageing-related ailments such as heart and liver diseases, and have been reported to be protective against toxic injuries to the liver. AIM OF THE STUDY: This study aimed to isolate and characterize the hepatoprotective/hepatotherapeutic principle in the methanol leaf extract of P. santalinoides. MATERIALS AND METHODS: Fresh leaves of P. santalinoides were dried under shade and ground into powder. The ground leaves (2 Kg) were extracted with 80% methanol by maceration. Fractionation was carried out using column and thin layer chromatography techniques. Bioassay of fractions and sub-fractions was done using carbon tetrachloride (CCl4)-induced hepatotoxicity model in albino rats. Phytochemical analysis was carried out on the active compound. Characterization and structural elucidation of the active compound using high performance liquid chromatography and nuclear magnetic resonance spectroscopy was done. RESULTS: Extraction yielded 260 g dry extract. Six fractions (F1, F2, F3, F4, F5 and F6) were obtained after column and thin layer chromatography, with F6 (Rf = 0.78; Yield = 2.13 g) being the most active hepatotherapeutic fraction that significantly (p < 0.05) lowered serum ALT activity and increased serum albumin levels in CCl4-induced hepatopathy in albino rats. Further separation of F6 yielded four sub-fractions (F61, F62, F63 and F64), of which F61 with an Rf of 0.85 and a yield of 30.0 mg was isolated as the active hepatotherapeutic compound. Stiasny and ferric chloride test of F61 showed the presence of tannins in the fraction. Characterization of F61 revealed 1, 3-di-ortho-galloyl quinic acid. CONCLUSION: The hepatoprotective/hepatotherapeutic principle in the methanol extract of the leaves of P. santalinoides was identified as 1, 3-di-ortho-galloyl quinic acid.

Bioactivity-guided isolation of the antidiabetic principle in Pterocarpus Santalinoides leaf extract

Abstract Pterocarpus santalinoides is used in Nigerian ethnomedicine to treat diabetes mellitus. This study aimed to establish the antidiabetic property of the plant, and isolate and characterize its active principle. Dried and pulverized leaves (500 g) of P. santalinoides were extracted with 1.8 L of 80 % hydromethanol by cold maceration. The dried extract (10 g) was partitioned into n-hexane, ethyl acetate (EtOAc), n-butanol, and water. Antidiabetic activitiy-guided isolation by column chromatographic separation of the EtOAc soluble and purification of the sub-fractions by repeated preparative thin layer chromatography (pTLC) yielded a C-glycosyl flavonoid, identified as isovitexin. The chemical structure was elucidated based on high-resolution mass spectroscopy, 1D, and 2D nuclear magnetic resonance spectroscopic analyses. Alloxan-induced diabetic rat model was adopted for antidiabetic screening. The extract of P. santalinoides (100-200 mg/kg), fraction F4 (50 mg/kg), sub-fraction F4.3 (10 mg/kg), and the semi-purified compound F4.3.2 (5 mg/kg) significantly (p<0.05) reduced the fasting blood glucose of alloxan-induced diabetic rats, causing 48.4, 69.4, 57.7 and 64.5 % antidiabetic activity respectively, compared with > 68 % recorded in glibenclamide (2 mg/kg) control. These results reveal that isovitexin is the antidiabetic principle in P. santalinoides

Combinations of Alchornea cordifolia, Cassytha filiformis and Pterocarpus santalinoides in diarrhoegenic bacterial infections.

OBJECTIVES: This study examines the rationale, if any, behind combining the extracts from the fruits of Alchornea cordifolia and Pterocarpus santalinoides and aerial parts of Cassytha filiformis in the traditional treatment of diarrhoegenic bacterial infections. RESULTS: Four diarrhoegenic bacterial isolates: Salmonella typhi, Shigellae dysenteriae, Escherichia coli and Staphylococcus aureus were used and their antibiotic susceptibility screening showed that they were multi-antibiotic resistant. The extracts exhibited activity against all the test isolates with minimum inhibitory concentration values ranging from 3.125 to 12.5 mg/mL. From the checkerboard assay, the fractional inhibitory concentration indices showed that C. filiformis has antagonistic and indifference activities in combination with either P. santalinoides or A. cordifolia. This showed that the combination of extracts from the fruits of A. cordifolia and P. santalinoides and aerial parts of C. filiformis is counterproductive and invalidates any claim for positive results in the management of diarrhoegenic bacterial infections.

Evaluation of antitrypanosomal activity of Pterocarpus santalinoides L'H'erit ex DC hydroethanol leaf extract in rats experimentally infected with Trypanosoma brucei.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Pterocarpus santalinoides are used alone or with other plants by traditional healers in some Southern Nigerian and Ivorian rural villages to treat blood parasitic infections including trypanosomiasis and malaria. However, their efficacy and safety remains doubtful. AIM: To evaluate the antitrypanosomal activity of Pterocarpus santalinoides hydroethanol leaf extract (PSELE) in vitro and in vivo. MATERIALS AND METHODS: The phytochemical and acute toxicity studies of PSELE were performed using standard methods. Eleven different concentrations of the extract were screened for in vitro antitrypanosomal activity. For the in vivo study, twenty-five female albino rats were randomly assigned into five groups of five rats each. Group A was the uninfected and untreated group while groups B - E were infected intraperitoneally with 106 trypanosomes. Group C rats were treated once on day 11 post infection (PI) with 7 mg/kg diminazene aceturate while groups D and E rats were also treated on same day with 200 mg/kg and 400 mg/kg PSELE respectively for seven days. The level of parasitaemia (LOP), survivability, packed cell volume (PCV), total leucocyte count (TLC), total erythrocyte count (TEC), body weight and rectal temperature were used to assess the antitrypanosomal effect of PSELE. RESULTS: Phytochemical analysis revealed the presence of flavonoids, tannins, carbohydrates and reducing sugar. No sign of toxicity or mortality was observed following acute toxicity study at a single dose of 2000 mg/kg. The LC50 of PSELE was 0.0625 mg/ml. Parasitaemia was first detected on day 8 and all infected rats became parasitaemic on day 10 (PI). PSELE significantly reduced (p < 0.05) LOP, improved PCV, TEC and prolonged survival time of the rats compared with the infected untreated group B. CONCLUSION: It was therefore concluded that PSELE is safe, possesses some antitrypanosomal activity and may serve as a lead for the development of an effective alternative antitrypanosomal drug.