Phytochemical composition and anti-inflammatory potential of Hermannia geniculata leaf extracts

Chronic inflammation contributes to the development of many non-communicable diseases; this causes high demand for safe plant-derived anti-inflammatory agents. Hermannia geniculata is a Basotho traditional medicine used to treat various ailments, and it remains poorly studied at the phytochemical level, especially its leaves. This study aimed to characterize the phytochemical composition of H. geniculata leaf extracts and evaluate their in vitro anti-inflammatory activity using a 5-lipoxygenase inhibition assay. Fresh leaves were collected from Phuthaditjhaba, South Africa, dried, powdered, and extracted using five solvents: acetone, ethanol, hexane, methanol, and distilled water. Qualitative and quantitative phytochemical analyses were performed to identify major classes of secondary metabolites. Total phenolic content (TPC) was determined using the Folin–Ciocalteu method. Anti-inflammatory activity was assessed using a 5-lipoxygenase (5-LOX) inhibition assay, with nordihydroguaiaretic acid (NDGA) as the positive control. Methanol produced the highest extraction yield (16.71 ± 2.43%) and the highest TPC (85.6 mg GAE/g), with ethanol showing comparable phenolic content (84.4 mg GAE/g). Qualitative screening revealed the presence of phenolics, flavonoids, alkaloids, tannins, glycosides, saponins, and phytosterols in multiple extracts, while anthraquinones were absent. All extracts exhibited weak 5-LOX inhibitory activity, with maximum inhibition of 18.13% at 0.40 mg/mL, compared with 84.93 ± 6.36% for the positive control. H. geniculata leaves contain diverse phytochemicals, with polar solvents demonstrating greater extraction efficiency. Although crude extracts showed limited 5-LOX inhibition, the phytochemical profile suggests potential for further investigation through extract fractionation and complementary anti-inflammatory assays to better evaluate the therapeutic potential of this species.