Phytochemical exploration of Oxygonum sinuatum and biological evaluation of isolates: Identification of oxylignoside and its absolute configuration

Authors: ELBERMAWI, AHMED - University Of Mississippi; ZULFIQAR, FAZILA - University Of Mississippi; KHAN, IKHLAS - University Of Mississippi; ALI, ZULFIQAR - University Of Mississippi

Submitted to: South African Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2025
Publication Date: 9/12/2025
Citation: Elbermawi, A., Zulfiqar, F., Khan, I.A., Ali, Z. 2025. Phytochemical exploration of Oxygonum sinuatum and biological evaluation of isolates: Identification of oxylignoside and its absolute configuration. South African Journal of Botany. 186(2025)/146–151. https://doi.org/10.1016/j.sajb.2025.09.001.
DOI: https://doi.org/10.1016/j.sajb.2025.09.001

Interpretive Summary: In the past few decades, medicinal plants, the foundation of traditional medicine, have been the focus of intensive pharmacological studies. This has been made possible by recognizing the value of medicinal plants as potential sources of new compounds with therapeutic value and lead compounds in drug development. Additionally, there is a sizable market for minimally processed medicinal plant parts that are typically prescribed as over-the-counter drugs, particularly in Europe and America. Oxygonum sinuatum (Polygonaceae) is a widespread annual herb that thrives in dry areas throughout Kenya. Traditional uses for the plant roots are for bilharzias (schistosomiasis) and leaf juice is used in the treatment of conjunctivitis, whereas stems are used to treat tonsillitis.  Other than emodin, no research has been done on the phytochemicals present in this plant.  The study expands the understanding of secondary metabolites of this genus and family and suggests possible synergistic effects in the crude extract as the basis for the plant’s traditional medicinal properties.

Technical Abstract: Oxygonum sinuatum (Polygonaceae) is a widespread annual herb that thrives in dry areas throughout Kenya. The methanolic extract of the entire plant had previously been shown to have anti-inflammatory and antioxidant effects. Other than emodin, no research has been done on the phytochemicals present in this plant. In this study, the aerial parts were extracted with methanol, fractionated by VLC, and purified using chromatographic techniques to get a new dihydrobenzofuran containing lignan glycoside (oxylignoside, 1), and 15 known compounds. The absolute configuration of 1 was determined by electronic circular dichroism. All compounds were evaluated for antimicrobial and antimalarial activities. Notably, none showed considerable activity against the tested microbial strains. It is worth mentioning that all compounds were isolated for the first time from this plant; compounds 2, 5, 6, and 8 were the first to be reported from the family Polygonaceae. Compounds 3, 4, and 7 were isolated from the genus Oxygonum for the first time. The study expands the understanding of secondary metabolites of this genus and family and suggests possible synergistic effects in the crude extract as the basis for the plant’s traditional medicinal properties.