Domingo A. Okorie

Anthelmintic activity of the stem bark extracts of Berlina grandiflora and one of its active principles, Betulinic acid

This study examines the anthelmintic activity of a methanol, hexane and ethylacetate extracts of Berlina grandiflora and purified betulinic acid, the major triterpenoid found in the extract. Caenorhabditis elegans, a free living soil nematode was used as in vitro model in the study. A suspension of worms was treated with the extracts. After seven days of incubation activity was assessed in terms of number of worms exhibiting motiliy. The results showed that methanol, hexane and ethylacetate fractions at 500 ppm showed anthelmintic activities in the order ethylacetate > methanol > hexane from the alcoholic crude extract. The isolated betulinic acid from the ethylacetate fraction at 100 and 500 ppm showed strong anthelmintic activities comparable to piperazine. These results confirm the traditional use of Berlina grandiflora as an anthelmintic and indicate that betulinic acid is the active component.

Anti-inflammatory and antioxidant activities and constituents of Platostoma africanum P. Beauv.

Hexane and dichloromethane extracts of Platostoma africanum P. Beauv., a plant popularly employed in Nigeria in the treatment of rheumatic symptoms, were evaluated for anti-inflammatory and antioxidant activities. Acute inflammatory effects were studied in the egg-albumin-induced rat paw edema. Both extracts produced significant (p < 0.05) and dose-dependent inhibition of the egg-albumin-induced pedal edema with the 400 mg kg−1 dose being markedly better than piroxicam. The hexane and dichloromethane extracts also showed significant antioxidant activity with the dichloromethane extract exhibiting an IC50 comparable to that of BHT, a synthetic antioxidant. Phytochemical investigation of the extracts afforded eight acidic pentacyclic triterpenes, namely, ursolic acid, oleanolic acid, epimaslinic acid, maslinic acid, corosolic acid, hyptadienic, euscaphic acid and tomentic acid, and a mixture of β-sitosterol and stigmasterol. These constituents are reported for the first time in the genus.

Triterpenes from the seed of Entandrophragma species

Abstract The seeds of Entandrophragma angolense and E. utile contained no limonoids, but protolimonoids were isolated and identified.

Constituents of the Essential Oils of Boswellia dalzielii Hutch. from Nigeria

Abstract The air-dried leaves of Boswellia dalzielli Hutch. on hydrodistillation gave an essential oil in a yield of 1.25 (v/w). The chemical composition of the essential oil was analyzed by GC and GC/MS. Twenty-nine compounds were identified, with α-pinene (45.7%) and α-terpinene (11.5%) being the predominant compounds. The abundance of monoterpenoids in this oil is in accordance with previous findings for the oils of this genus.

Mutagenicity of chamuvaritin: A benzyldihydrochalcone isolated from a medicinal plant

The mutagenic effects of chamuvaritin, dihydrobenzylchalcone isolated from Uvaria chamae, were investigated using Salmonella typhimurium tester strains TA92, TA94--98, TA100--1535, TA1537 and TA1538. The phytochemical was mutagenic in tester strains TA98 and TA100 and required activation by the hepatic S-9 microsomal enzyme preparation.

Structure of dregeanin and rohitukin, limonoids from the subfamily Melioideae of the family Meliaceae. An unusually high absorption frequency for a six-membered lactone ring

A new group of limonoids, characterised by the possession of a seven-membered lactone ring A, a secoring B, and a five-membered carbocyclic ring D, has been discovered in the sub-family Meliodieae; a C(1)-C(7) lactone occurring in certain of these is characterised by an unusually high frequency carbonyl absorption in the i.r. spectra.

Limonoid extractives from species of Guarea. An unusual shielding effect on an acetyl group

The bark of Guarea species has been found to be a rich source of limonoids. One has been identified as methyl 6,12α-diacetoxyangolensate (1; R = OAc); the 12-acetyl group in this is strongly shielded by the furan ring.

Sesquiterpenes from Culcasia scandens P. Beauv.

From Culcasia scandens P. Beauv., carota-4(5), 11(12)-diene (isodaucene), carota-3(4), 11(12)-dien-5-one, a new epoxide, 4,5-epoxy-carota-11(12)-ene (isodaucene epoxide) and β-caryophyllene epoxide were isolated. The structures were established spectroscopically. Epoxidation of isodaucene with m-CPBA confirmed the structure and stereochemistry of the new epoxide.