Phytochemical characterization and cytotoxicity effects of Hyptis suaveolens collected in Nigeria

• First isolation and characterization of 14- O -acetyl suaveolol from Nigerian Hyptis suaveolens leaves. • Hyptis suaveolens metabolites have moderate to strong cytotoxicity against cancer cells. • The acetyl group location in suaveolol derivatives may play a vital role in cancer cells. Hyptis suaveleons (L.) Poit. belongs to the Laminaceae family. This weed, native to tropical America, has become widespread in tropical regions worldwide. In folk medicine, plant extracts are used in the treatment of wounds, peptic ulcers, respiratory tract infections, and skin diseases among others. Thus, the importance of assessing the toxicity of plants for any human use cannot be overstated. This study analyzed the phytochemical properties of the Nigerian H. suaveleons population and assessed its cytotoxicity. Six bioactive compounds were isolated from the acetone extract of the H. suaveolens plant using silica gel column chromatography, one of which is new from natural sources. The isolated compounds were identified as 14- O -acetyl suaveolol ( C1 ), suaveolol ( C2 ), suaveolic acid ( C3 ), dehydroabietinol ( C4 ), maniladiol ( C5 ), and β-sitosterol ( C6 ) based on 1D and 2D NMR spectroscopic data. The MTT assay was used to assess the cytotoxicity effects of these metabolites on HepG2, KMST-6, and HaCaT cells. Among them, C1 significantly reduced HepG2, KMST-6, and HaCaT cell viability with IC 50 values of 35.97, 43.48, and 65.10 µg/ml, respectively. The study suggests C1 has promising anticancer properties, possibly due to the acetyl group on C-14, while C2 , suaveolol, lacks this group, and did not yield any inhibitory activities. However, further research is needed to understand its mechanisms.