Phytotoxic and Cytotoxic Polyketides Produced by Fungal Endophytes Isolated from Psidium guajava

Endophytic fungi reside within their host plants with no obvious symptoms. They have been proven as abundant sources of new bioactive compounds diverse structures. In our continuous search the compound from endophytic fungi, a compound, 5,7-dihydroxy-3(R)-methylphthalide (1), was isolated Xylaria brevipes PGR1, and three known compounds, (–)-altenuene (2), alternariol (3), altertoxin I (4), were Alternaria alternata D-8. Both branch an Indonesian medicinal plant, Psidium guajava. Their structures elucidated using extensive spectroscopy analyses, including 1D/2D NMR, HRESITOFMS, data comparisons literature. Compounds 1–3 exhibited phytotoxicity at IC50 (µg/ml) values 4.6, 23.07, 77.28, respectively. Additionally, 1–4 showed significant cytotoxicity in brine shrimp lethality test (BSLT), mortality rates 75%, 50%, 90%, 80% concentration 0.19 μg/ml,