The search for new molecular constructs that resemble the critical two-metal binding pharmacophore and the halo-substituted phenyl functionality required for HIV-1 integrase (IN) inhibition represents a vibrant area of research within drug discovery. As reported herein, we have modified our recently disclosed 1-[2-(4-fluorophenyl)ethyl]-pyrrole-2,5-dione scaffolds to design 35 novel compounds with improved biological activities against HIV-1. These new compounds show single-digit micromolar antiviral potencies against HIV-1 and low toxicity. Among of them, compound 9g and 15i had potent anti-HIV-1 activities (EC₅₀ < 5 μM) and excellent therapeutic index (TI, CC₅₀/EC₅₀ > 100). These two compounds have potential as lead compounds for further optimization into clinical anti-HIV-1 agents.

APOBEC3G is a member of the human cytidine deaminase family that restricts Vif-deficient viruses by being packaged with progeny virions and inducing the G to A mutation during the synthesis of HIV-1 viral DNA when the progeny virus infects new cells. HIV-1 Vif protein resists the activity of A3G by mediating A3G degradation. Phorbol esters are plant-derived organic compounds belonging to the tigliane family of diterpenes and could activate the PKC pathway. In this study, we identified an inhibitor 12-O-tricosanoylphorbol-20-acetate (hop-8), a novel ester of phorbol which was isolated from Ostodes katharinae of the family Euphorbiaceae, that inhibited the replication of wild-type HIV-1 and HIV-2 strains and drug-resistant strains broadly both in C8166 cells and PBMCs with low cytotoxicity and the EC₅₀ values ranged from 0.106 μM to 7.987 μM. One of the main mechanisms of hop-8 is to stimulate A3G expressing in HIV-1 producing cells and upregulate the A3G level in progeny virions, which results in reducing the infectivity of the progeny virus. This novel mechanism of hop-8 inhibition of HIV replication might represents a promising approach for developing new therapeutics for HIV infection.

The anti-HIV activities of a pine cone extract (YNS-PY-F) from Pinus yunnanensis have been evaluated, and its mechanisms of action were also explored. The pine cone extract, YNS-PY-F, potently inhibited HIV-1_IIIB, HIV-1_RF, HIV-1_A17, HIV-1_AO18 and HIV-2_ROD and induced cytopathic effect in C8166 cells with EC₅₀ values of 0.96 μg/mL, 1.53 μg/mL, 0.88 μg/mL, 7.20 μg/mL and 6.17 μg/mL, respectively. The quantification of a p24 production assay showed that YNS-PY-F significantly inhibited the acute replication of HIV-1_IIIB, HIV-1_RF, HIV-1_A17 and HIV-1_AO18 in C8166 cells. An MTT assay showed that YNS-PY-F also significantly inhibited the HIV-1_IIIB induced cytolysis in MT-4 cells with an EC₅₀ value of 2.22 μg/mL. The mechanism assays showed that YNS-PY-F had potent inhibitory effects on the fusion between infected cells and uninfected cells, and the activity of HIV-1 reverse transcriptase, with EC₅₀ values of 7.60 μg/mL and 4.60 μg/mL, respectively. Overall, these data suggest that the pine cone extract from Pinus yunnanensis has potent inhibitory activities against HIV-1_IIIB, HIV-1_RF, RT inhibitor-resistant strains HIV-1_A17 and HIV-1_AO18, and HIV-2_ROD, and its anti-HIV mechanisms include inhibition of HIV entry and inhibition of reverse transcriptase activity.

Three new unusual 23-spirocholestane derivatives, ypsilanogenin (1), ypsilanogenin 3-O-β-D-glucopyranoside (2), and 4′-acetylypsilanogenin 3-O-β-D-glucopyranoside (3), were isolated from the whole plants of Ypsilandra thibetica. The structures of compounds 1–3 were deduced by spectroscopic and chemical methods, and the structure of 1 was further confirmed by a single-crystal diffraction analysis. All isolates were evaluated for their inhibitory activities against HIV-1.

Latent reservoir persistence remains a major obstacle for curing human immunodeficiency virus type 1 (HIV-1) infection. Thus, strategies for the elimination of latent HIV-1 are urgently needed. As a bromodomain and extra-terminal (BET) inhibitor, BMS-986158 has been used in clinical trials for advanced solid tumors and hematological malignancies. Here, we found that BMS-986158 reactivated latent HIV-1 in three types of HIV-1 latency cells in vitro, and in combination antiretroviral therapy (cART)-treated patient-derived peripheral blood mononuclear cells ex vivo, without influencing global immune cell activation. BMS-986158 reactivated latent HIV-1 by increasing phosphorylation of CDK9 at Thr186 and promoting recruitment of CDK9 and RNA polymerase II to the HIV-1 long terminal repeat in J-Lat cells. Furthermore, BMS-986158 exerted strong synergism in reactivating latent HIV-1 when combined with prostratin and vorinostat and enhanced the antiviral activity of anti-HIV-1 drugs. Finally, BMS-986158 showed antiviral activity in an HIV-1 acute infection model, possibly by arresting the cell cycle in infected cells. Thus, these results suggest that BMS-986158 is a potential candidate for AIDS/HIV-1 therapy.