Sperm-disrupting activity of a root bark fraction of Flueggea virosa (Roxb. ex willd.) royle uncovered using LC-MS/MS profiling and functional evaluation

Abstract

Introduction: While Flueggea virosa (Roxb. Ex Willd.) Royle root bark is traditionally used in several parts of East Africa for fertility regulation, its contraceptive potential has not been systematically investigated. Given the paucity of safe, reversible, non-hormonal contraceptives for women, this study evaluated a root bark fraction for sperm-disrupting, intravaginal contraceptive activity using functional assays and a rabbit proof-of-concept model. Methods: Following extraction and fractionation of authenticated root bark, the resulting extracts were evaluated for cytotoxicity in Vero cells and for disruption of human sperm functions by ascertaining immobilization, revival, viability, cervical mucus penetration and acrosin-related activity. Thereafter, chemical profiling of the most active fraction was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for descriptive annotation. Moreover, in vivo contraceptive efficacy and short-term local safety (10 days) were determined after intravaginal administration of the fraction in rabbits by histological examination of cervicovaginal tissues. Results: The methanolic fraction (KBLM) demonstrated the strongest activity, completely immobilizing sperm, abolishing sperm revival after washing, markedly reducing sperm viability, strongly inhibiting cervical mucus penetration and suppressing acrosin-related activity at 1.62 mg/mL. In a rabbit proof-ofconcept experiment, a single intravaginal dose prevented pregnancy at all tested concentrations (3.9, 7.8, and 15.6 mg/mL). Besides, repeated OPEN ACCESS EDITED BY Maša Knez Marevci, University of Maribor, Slovenia REVIEWED BY Tushar Dhanani, Florida Agricultural and Mechanical University, United States Parasuraman S, AIMST University, Malaysia *CORRESPONDENCE Kehongo M. Nyanguru, kehongo@mmarau.ac.ke, kehongomoses1995@gmail.com Elizabeth Kigondu, m_kigondu@yahoo.com, ekigondu@kemri.go.ke RECEIVED 20 March 2026 REVISED 11 June 2026 ACCEPTED 15 June 2026 PUBLISHED 01 July 2026 CITATION Nyanguru KM, Maina C, Ibrahim M, Kuria J, Ndirangu E, Njeru SN, Abdulraheem A, Murungi E, Obimbo M, Aremu AO, Osano AM, Cheruiyot S, Ilomuanya MO, Mwangi PW and Kigondu E (2026) Spermdisrupting activity of a root bark fraction of Flueggea virosa (Roxb. ex willd.) royle uncovered using LC-MS/MS profiling and functional evaluation. Front. Pharmacol. 17:1835308. doi: 10.3389/fphar.2026.1835308 COPYRIGHT © 2026 Nyanguru, Maina, Ibrahim, Kuria, Ndirangu, Njeru, Abdulraheem, Murungi, Obimbo, Aremu, Osano, Cheruiyot, Ilomuanya, Mwangi and Kigondu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Frontiers in Pharmacology 01 frontiersin.org intravaginal exposure for 10 days revealed absent-to-mild cervicovaginal changes. Chemical fingerprinting putatively annotated flavonoid-, tannin-, and phenolicrelated features, including catechin, quercetin derivatives, rutin, corilagin, and kaempferol glycosides, as prominent features of KBLM. Conclusion: Our findings have demonstrated the sperm disruption activity of the methanolic fraction of F. virosa root bark. The observed disruption of multiple sperm functions, observed efficacy in a rabbit model and absent-to-mild shortterm local tissue changes support additional preclinical investigations of the extract geared towards further functional characterization, extended safety testing, standardization, and potential formulation of an intravaginal contraceptive.