Phycochemical studies on sterols from three brown seaweeds of northern Arabian Sea

Three brown algae i.e. Dictyota hauckiana Nizamuddin, Levringia boergesenii Kylin and Spatoglossum variabile Figari et De Notaris, collected from the coastal areas of Karachi, have been investigated for their sterol composition. Four sterols with cholesta skeleton including a new one, 17α-hydroxy-24β-vinyl cholesterol have been isolated from them. Their structures were elucidated with the help of spectroscopic analysis. The new sterol has been named as hauckiosterol after its first source of isolation

Isolation and structure elucidation of a new oleanane type glycoside from the aerial portion of Cestrum nocturnum

Cestrum nocturnum (Solanaceae) is an ornamental plant cultivated in various parts of the world due to its sweet-scented white flowers. It is commonly called night-blooming Jessamine (Raat ki Rani). The genus is known for its toxicity to feedents. The leaves may cause uneasiness in animals which may lead to severe gastroenteritis. The plant is known to be a rich source of pharmacologically active saponins. Looking to its various pharmacological activities as reported, the plant was explored for the isolation of new phytochemicals. During the process, a new oleanen type glycoside was isolated from the butanolic fraction of the leaves of Cestrum nocturnum and was characterized as 3-O-β-D-xylopyranoside-olean-12-en-28-oic acid-28-O-β-arabinopyranosyl-(1-3)-β-D-galacto-pyranosyl-(1-2)-β-D-glucopyranosyl-(1-4)-β-D-glucopyranosyl ester, along with two reported compounds nocturnoside A and karativoside A. The structure was elucidated on the basis of 1D and 2D NMR and mass spectrometry.   Bull. Chem. Soc. Ethiop. 2020, 34(1), 141-148. DOI: https://dx.doi.org/10.4314/bcse.v34i1.1

A new triterpenoid saponin from the stem bark of Pometia pinnata

Phytochemical investigation of the stem bark of Pometia pinnata resulted in the isolation of a new triterpenoidal saponin. The structure of the new compound, pometin (1), was established as 3-O-[beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 3)-beta-D-glucopyranosyl]-oleanolic acid based on 1D and 2D-NMR analysis including COSY, 2D J-resolved, HMQC, HMBC correlations and chemical transformations

Bioactivity of seaweeds against soil-borne plant pathogens

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