Four meroterpenoids from the leaves of <i>Psidium guajava</i> L. and their cytotoxicity activities

In this study, two previously undescribed meroterpenoids, Psidiguajadiol G (<b>1</b>) and H (<b>2</b>), together with 2 known analogues, were isolated from leaves of <i>Psidium guajava</i> L. Their structures were confirmed by comparative analysis of spectroscopic analyses, calculated and measured electronic circular dichroism (ECD). Further <i>in vitro</i> experiments were used to detect cytotoxicity, anti-proliferation and apoptosis/necrosis effects of compounds in variously cancer cells. Our results confirmed that compound 1 and 2 exhibited broad spectrum cytotoxicity effects in cancer cells. The cytotoxicity effects of compound 1 were MCF-7 > OVCAR-3 > SKOV3 ≈ MDA-MB-231 > HCT116 > H1299 > 22Rv1. Compound 1 and 2 exerted significantly killing effects in women highly prevalent breast and ovarian cancer by inhibiting cell proliferation, promoting necrotic cell death and apoptotic programmed death. Compounds 3 and 4 showed slightly lower cytotoxic effects on tumour cells, and also exhibited different killing effects between female cancers and male cancer.