Benstolizidines A-E: Indolizidine- and piperidine-type alkaloids from Benstonea parva

Five previously undescribed indolizidine- and piperidine-type alkaloids, named benstolizidines A-E (1-5), were isolated from the leaves of Benstonea parva. The structures and absolute configurations of these alkaloids were determined using comprehensive spectroscopic methods, including GIAO NMR calculations, DP4+ probability analysis, TDDFT-ECD method, and X-ray crystallography. A plausible biosynthetic pathway for these alkaloids was proposed. Bioassay studies revealed that indolizidine compounds 1, 2, and 4 exhibited weak cytotoxic activity, consistent with previous findings on indolizidine alkaloids from Pandanus species. However, compounds 1-4 notably extended the lifespan of C. elegans, with compound 2 exhibiting the most significant effect, increasing longevity by up to 9% compared to untreated controls. These findings suggest the promising therapeutic potential of these alkaloids in addressing age-related and degenerative diseases.