Hyptis suaveolens, an alternative source of podophyllotoxin?

Through a screening program of the Mexican medicinal flora based on chemotaxonomical and ethnobotanical criteria, the species Hyptis suaveolens was selected as a potential candidate for producing lignans of the podophyllotoxin group. When testing the cytotoxic activity of chloroform extracts obtained from various plant parts (roots, stems and leaves) againts nasopharyngeal (KB), colon (HF6) and breast (MCF7) cancer cell lines, EC₅₀ values showed significant activities lower than 10µg/mL. The root extract was the most active one, with an EC₅₀ value of 2.6µg/mL against MCF7. The presence of podophyllotoxin in this bioactive extract was confirmed by LC-MS and ¹H-NMR spectroscopy and podophyllotoxin derivatives were isolated and characterized in the wild plant material.

Finally, in vitro cultures (plantlets and calluses) were developed and the podophyllotoxin accumulation was evaluated through an optimized HPLC methodology, potentially leading to a sustainable biotechnological approach of producing this anticancer drug. Additional biological testing of chloroform and butanolic extracts from this plant, showed antibacterial activity against Gram negative (E. coli, S. typhi) as well as Gram positive (S. aureus, B. subtilis) bacteria, with inhibition zones of 11–14mm diameter caused by 1mg of extracts.

Acknowledgements: Luis Manuel Peña, Alexandre Taketa, Vickram Beejmohun.