Eight new aspulvinone analogues, aspulvins A–H ( 1 – 8 ) and aspulvinones D, M, O, and R ( 9 – 12 ), were isolated from cultures of the endophytic fungus Cladosporium sp. 7951. Detailed spectroscopic analyses were conducted to determine the structures of the new compounds. All isolates displayed different degrees of inhibitory activity against the severe acute respiratory syndrome coronavirus 2 main protease (SARS-CoV-2 M pro ) at 10 μM. Notably, compounds 9 , 10 , and 12 showed potential SARS-CoV-2 M pro inhibition with IC 50 values of 10.3 ± 0.6, 9.4 ± 0.6, and 7.7 ± 0.6 μM, respectively. For all compounds except 3 and 4 , the anti-inflammatory activity occurred by inhibiting the release of lactate dehydrogenase (LDH) with IC 50 values ranging from 0.7 to 7.4 μM. Compound 10 showed the most potent anti-inflammatory activity by inhibiting Casp-1 cleavage, IL-1β maturation, NLRP3 inflammasome activation, and pyroptosis. The findings reveal that the aspulvinone analogues 9 , 10 , and 12 could be promising candidates for coronavirus disease 2019 (COVID-19) treatment as they inhibit SARS-CoV-2 infection and reduce inflammatory reactions caused by SARS-CoV-2.

Wulfenioidins A−C (1−3) with an unprecedented 6/5−5 tricyclic skeleton featuring unusual spiro [4.4] nonane were isolated from the whole plant of Orthosiphon wulfenioides. Their structures were elucidated by X-ray diffraction,...

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Twelve new clerodane diterpenoids named callicarpanes A -L (1 -12), together with eight known compounds (13 -20), were isolated from Callicarpa integerrima. Their structures were determined by comprehensive spectroscopic data. The calculated chemical shifts were used to identify relative configurations using DP4 + analysis. The absolute configurations (AC) were assigned based on quantum chemical calculations and X-ray single-crystal diffraction methods. Compounds 1, 3, 5, 9, 10, 12, 15, 16, and 19 showed significant inhibitory activity for NLRP3 inflammasome activation, with the IC 50 against lactate dehydrogenase (LDH) release ranging from 0.08 to 4.78 μM. Further study revealed that compound 10 repressed IL-1β secretion and caspase-1 maturation in J774A.1 cell as well as blocked macrophage pyroptosis.