IL-6 Inhibitory Compounds from the Aerial Parts of Piper attenuatum and Their Anticancer Activities on Ovarian Cancer Cell Lines

Buch-Ham, a perennial woody vine belonging to the Piperaceae family, is traditionally used in Southeast Asia for treating various ailments such as malaria, headache, and hepatitis. This study described the isolation and identification of three new compounds, piperamides I-III ( - ), which belong to the maleimide-type alkaloid skeletons, along with fifteen known compounds ( - ) from the methanol extract of the aerial parts of . Their chemical structures were elucidated using spectroscopic methods (UV, IR, ESI-Q-TOF-MS, and 1D/2D NMR). All the isolates were evaluated for their ability to inhibit IL-6 activity in the human embryonic kidney-Blue™ IL-6 cell line and their cytotoxic activity against ovarian cancer cell lines (SKOV3/SKOV3-TR) and chemotherapy-resistant variants (cisplatin-resistant A2780/paclitaxel-resistant SKOV3). The compounds , , , , , and exhibited IL-6 inhibition comparable to that of the positive control bazedoxifene. Notably, compound displayed the most potent anticancer effect against all the tested cancer cell lines. These findings highlight the importance of researching the diverse activities of both known and newly discovered natural products to fully unlock their potential therapeutic benefits.