Phytochemical screening, antibacterial and cytotoxic activities of Aristolochia philippinensis Warb. leaf extracts

The Aristolochia philippinensis Warb. (Aristolochiaceae) is commonly used in traditional medicine among indigenous people in the Philippines. The leaves of A. philippinensis are used to treat illnesses such as stomach aches, bodily aches, and physical relapse. This study was conducted to identify the phytochemical compounds and evaluate the antibacterial and cytotoxic activity of A. philippinensis. The leaf extracts were subjected to qualitative phytochemical screening, in vitro testing for antibacterial activity using agar well-diffusion assay against selected gram-positive and gram-negative bacteria and cytotoxic activity using 3-(4,5-dimethylthiazol-2-y-l)-2,5-diphenyltetrazolium bromide (MTT) cell viability assay against human colorectal carcinoma cells (HCT 116). The results of the phytochemical screening of the leaf extracts showed that leaf extracts contain flavonoids, tannins, alkaloids, and steroids; however, there is an absence of saponins, anthraquinones, and cyanogenic glycosides. The agar well-diffusion assay also revealed that leaf extracts have inhibitory effects on all test organisms but are relatively lower compared to the control (Chloramphenicol). In contrast, aqueous leaf extract showed no inhibitory effects. Furthermore, the MTT cell viability assay demonstrated that leaf extracts inhibited the growth of HCT116 effectively with a half-maximal inhibitory concentration (IC50) of 141.57 ppm than the aqueous extract with an IC50 of 506.66 ppm. This study demonstrated that the use of A. philippinensis has a pharmacological basis as an ethnomedicine and could be vital in drug discovery.