Phytochemical studies, in vitro antioxidant and antiproliferative of the stem bark of Boswellia dalzielii hutch

This work aims to evaluate the total phenolic and flavonoid contents, and antioxidant and Antiproliferative activities of the stem bark of Boswellia dalzielii. Hundred gram (100 g) of methanolic extract was re-dissolved in 70% methanol and partitioned exhaustively with different solvent hexane and ethyl acetate in a separating funnel; and this method gave three fractions, hexane fraction, ethyl acetate fraction and aqueous extract. The ethyl acetate fraction was subjected to Accelerated Gradient Chromatographic due to its higher activity over the hexane fraction and four sub-fractions were obtained. Standard methods were used to determine flavonoid and phenolic contents of the methanolic, aqueous, ethyl acetate and hexane fractions and their sub-fractions. Standard methods were used to determine flavonoid and phenolic contents of the methanolic, aqueous, ethyl acetate and hexane extracts and their sub-fractions. The antioxidant property of the extracts was determined using DPPH radical scavenging and FRAP assay. Growth inhibitory activity was carried out on the crude extracts and sub-fractions using Sorghum bicolor seeds. The phenolic content was found to be highest in sub-fraction C (481.20 ± 10.13 mg GAE/g) and flavonoid contents were found to be highest in methanolic extract (142.17 ± 4.82 mg RE/g). Boswellia dalzielii stem bark exhibited antioxidant capacity; and the highest antioxidant activities were recorded from aqueous extract with the IC50 1.58 and methanol extract IC50 1.99 using DPPH. FRAP assay exhibited antioxidant capacity with EC50 1.00 for aqueous extract and sub-fraction D EC50 1.25. The antiproliferative, sub-fractions C and D at 125 µg/ml gave the highest percentage of inhibition (90%) followed by sub-fraction B (50%) at 250 µg/ml. These results further showed that the stem bark of Boswellia dalzielii has antioxidant activities and antiproliferative activity on the seeds of Sorghum bicolor; and therefore possess likely an anticancer component which needs further anticancer screening

Isolation and characterization of β-sitosterol, oleanolic, 19- dehyroursolic and yarumic acids, from Plectranthus esculentus leaves and tubers

Plectranthus esculentus N.E.Br. (family Lamiaceae) also known as Livingstone potato (vat or rizga in Nigeria), is a dicotyledonous perennial shrub growing up to 2 m tall. While it is cultivated mainly for its edible tubers, the plant is potentially valuable as phytomedicine. Three varieties (vat-long’at, vat-riyom and vat-bebot) are well known among the Berom of Plateau State, Nigeria. The vat-bebot variety (which showed good promise in bioactivity studies) was used in this study. The leaves and tubers were extracted successively with hexane, ethyl acetate, methanol and water. Fractionation of the active ethyl acetate extracts was carried out using open column and preparative High Performance Liquid Chromatography (prep HPLC). This led to the isolation of β-sitosterol and oleanolic acid from the leaves; while 19-dehydroursolic acid and yarumic acid, as well as β-sitosterol were isolated from the tubers. Nuclear Magnetic Resonance (NMR) and Electron Impact Mass Spectroscopy (EIMS) were used to characterize isolated compounds. Comparing acquired spectral data of isolated compounds with those from literature helped to confirm the identity of the compounds. The isolation and characterisation of these compounds, from Plecthranthus esculentus, have not been hitherto reported in literature

Antiproliferative, antioxidant and antiplasmodial activities of the root bark of Adenodolichos paniculatus (Hua) Hutch (Fabaceae)

Adenodolichos paniculatus Hua & Hutch (Fabaceae) is a plant whose roots are traditionally employed for the treatment of non-communicable diseases such as diabetes and cancer. The powdered root bark of Adenodolichos paniculatus were extracted with dichloromethane followed by 70% methanol to afford dichloromethane (DCM) and hydromethanolic (HME) extracts respectively. Thereafter, fresh powdered root was extracted with water via decoction method and lyophilized to afford aqueous extract (AQE). The extracts were then subjected to standard phytochemical studies, antiproliferative (A2780 ovarian cancer cell assay), antiplasmodial (Dd2 strain of Plasmodium falciparum), antioxidant (DPPH, FRAP and ABTS methods) and brine shrimp lethality assay studies. The DCM extract was found to possess high levels of total phenolics and flavonoids with notable potential antiproliferative (IC50 = 0.14 μg/ml), antiplasmodial (IC50 = 7.50 μg/ml) and cytotoxic (brine shrimp, IC50 = 0.547 μg/ml) activities. However, HME had significant antioxidant (DPPH, IC50 = 17.54 ± 0.03 μg/ml; ABTS, IC50 = 8.08 ± 0.05 μg/ml). Both HME and AQE were found to be inactive against the drug-resistant Dd2 strain of Plasmodium falciparum with an IC50 value ˃100μg/mL. The study revealed the potential of Adenodolichos paniculatus as a promising antiproliferative agent and also corroborated the ethnomedical uses of the plant

Brine shrimp toxicity of acidic fractions of Boswellia dalzielii gum resin

Boswellia dalzielii is the West African species of the frankincense producing genus ( B. carterii, B. frereana and B. serrata are the more popular congeners). Its ethnobotanical uses include the treatment of rheumatism, venereal diseases and gastro-intestinal disorders, swellings/ growths on the skin, among other things. The anti-inflammatory, anti-hyperlipidemic and immunomodulatory activities of B. serrata gum resin have been established as being due to triterpenoic (boswellic) acid derivatives such as b-boswellic acid, 3–O-acetyl–b–boswellic acid, 11–keto-b-boswellic acid and 3–O-acetyl–11-keto-b-boswellic acid. It was therefore considered pertinent to study the cytotoxic activity of the acidic fraction of B. dalzielii gum resin. The gum resin of B. dalzielii was extracted with diethyl ether and partitioned into acidic and neutral/basic fractions. These fractions had earlier been shown to have significant anti-inflammatory activity. The acidic fraction was fractionated into four sub-fractions (A-D) using Accelerated Gradient Chromatography (AGC). The fractions and sub-fractions, when tested for brine shrimp lethality, showed very high activity (LC5050µg/mL). Also the acidic fraction had a significantly higher activity over the neutral fraction. Being the most active, sub-fraction D (LC50 = 0.0013µg/mL) was subjected to AGC on silica. This afforded two pure compounds which, from preliminary chemical tests, were shown to be triterpenoids. Journal of Pharmacy & Bioresources Vol. 2(2) 2005: 137-14

Isolation and characterization of incensole from Boswellia dalzielii stem bark

Boswellia dalzielii is the West African species of the frankincense genus. It is used in ethnomedicine to treat gastrointestinal disorders, rheumatism and various diseases of microbial origin. The dried pulverized bark material was extracted with 50% ethanol by percolation. Column chromatography, gel filtration and preparative thin-layer chromatography (TLC) of the ethyl acetate fraction yielded incensole, a cembrane diterpenoid. Its structure was established by nuclear magnetic resonance (NMR) spectroscopy, including 2-D NMR experiments (reported here for the first time), and fast atom bombardment mass spectrometry (FAB-MS). Tests for antimicrobial and antioxidant (free-radical scavenging) activities revealed that while the extracts and fractions demonstrated strong antioxidant and antimicrobial activities, incensole was only moderately active. Key Words: Boswellia dalzielii; Incensole; Diterpenoid; Antimicrobial activity; Antioxidant activity; Journal of Pharmacy and Bioresources Vol.1(1) 2004: 7-1