Isolation, Structure Elucidation, and Bioactivity Evaluation of Two Alkaloids From Piper chaba H. Stem: A Traditional Medicinal Spice and Its Chemico-Pharmacological Aspects

Bangladesh is endowed with an abundance of excellent medicinal plant resources. A well-known traditional medicinal plant Piper chaba H. from the Piperaceae family is rich in bioactive phytochemicals that have antidiarrheal, antimicrobial, analgesic, antioxidant, anticancer, and cytotoxic effects. This plant is locally known as "Chuijhal," and the stem is used as spices. In the current research program, the stems of the P. chaba plant were selected and its chemical and biological investigations such as antidiarrheal, antimicrobial, and analgesic effects were performed. Moreover, docking models were accomplished by exploiting PyRx-Virtual Screening software and implied that isolated compounds of P. chaba exert different pharmacological activity by inhibiting their targeted receptors. Phytochemical investigations revealed the isolation of Chingchengenamide A, a relatively rare alkaloid from the stems of P. chaba. Another alkaloid Chabamide I which is a piperine dimer was also isolated. Their structures were confirmed by comparing these compounds' spectral data (1H and 13C NMR) with their previously published spectral data. Antidiarrheal activity shows a percent reduction of diarrhea by 46.67% and 40%, respectively, for Chabamide I and Chingchengenamide A (at 20 mg/kg b.w.) compared with an 80% reduction by standard loperamide. Similarly, the percent reduction of writhing was 53.06% and 42.86%, respectively, for Chabamide I and Chingchengenamide A at similar doses compared with an 80% reduction by diclofenac sodium considered as standard. Both the alkaloids showed auspicious outcomes against test microorganisms during disk diffusion antimicrobial assay. Molecular docking and ADME/T analysis of the alkaloids also validate a potent pharmacological basis for the traditional utilization of P. chaba in treating diarrhea, pain, and microbial infection. These results emphasize the need to investigate P. chaba as a potential source of natural therapies for common health issues, laying the foundation for future research.