Ursane and 24-Noroleanane-Type Triterpenoids with Anti-HIV Activity from the Twigs and Leaves of Antirhea chinensis.

Investigations on the twigs and leaves of Antirhea chinensis have led to the discovery of two undescribed pentacyclic triterpenoids (1 and 2) and nine known analogs. Compounds 1 and 2, each assigned as the ursane and 24-noroleanane-type triterpenoids, featuring similar oxidation pattern of 3ß,6ß,19α-trihydroxy-28-carboxyl. Their structures were elucidated via comprehensive analyses of spectroscopic data. Compound 1 displayed potent anti-HIV activity (EC50 =1.24 µM) and high selectivity index (SI >32.3).

Identification of resveratrol analogs as potent anti-dengue agents using a cell-based assay.

Dengue virus (DENV) causes a variety of difficult-to-treat diseases that threaten almost half of the world's population. Currently, no effective vaccine or antiviral therapy is available. We have examined a series of synthetic resveratrol analogs to identify potential anti-DENV agents. Here, we demonstrate that two resveratrol analogs, PNR-4-44 and PNR-5-02, possess potent anti-DENV activity with EC50 values in the low nanomolar range. These two resveratrol analogs were shown to mainly target viral RNA translation and viral replication, but PNR-5-02 is also likely to target cellular factors inside host cells. Although the precise molecular mechanism(s) mediating anti-DENV activities have not been elucidated, further structure-guided design might lead to the development of newer improved resveratrol derivatives that might have therapeutic value. J. Med. Virol. 89:397-407, 2017. © 2016 Wiley Periodicals, Inc.

Flueggether A and Virosinine A, Anti-HIV Alkaloids from Flueggea virosa.

Two new alkaloids, flueggether A (1) and virosinine A (2), were isolated from a Chinese medicinal plant, Flueggea virosa. Their structures were assigned via spectroscopic methods with the absolute configurations of 1 and 2 being established by X-ray diffraction analysis and calculated electronic circular dichroism data, respectively. Compound 1 represents the first example with an ether bridge of Securinega alkaloid oligomers, and 2 bears a new heterocyclic backbone. Both alkaloids showed mild in vitro anti-HIV activity.

Identification of a dibenzocyclooctadiene lignan as a HIV-1 non-nucleoside reverse transcriptase inhibitor.

BACKGROUND: Due to resistance to all classes of anti-HIV drugs and drug toxicity, there is a need for the discovery and development of new anti-HIV drugs. METHODS: HIV-1 inhibitors were identified and biologically characterized for mechanism of action. RESULTS: We identified a dibenzocyclooctadiene lignan, termed HDS2 that possessed anti-HIV activity against a wide variety of viral strains with EC50 values in the 1-3 µM range. HDS2 was shown to act as an NNRTI by qPCR and in vitro enzyme assays. CONCLUSIONS: This compound provides a new scaffold for further optimization of activity through structure-guided design.

Eurifoloids A-R, structurally diverse diterpenoids from Euphorbia neriifolia.

Eighteen new diterpenoids, named eurifoloids A-R (1-18), including ingenane (1 and 2), abietane (3-7), isopimarane (8-12), and ent-atisane (13-18) types, along with four known analogues were isolated from Euphorbia neriifolia. Eurifoloid M (13) represents a rare class of ent-atisane-type norditerpenoid. Eurifoloids E (5) and F (6) exhibited significant anti-HIV activities, with EC50 values of 3.58 ± 0.31 (SI = 8.6) and 7.40 ± 0.94 µM (SI = 10.3), respectively.