Oregano Oil and Its Principal Component, Carvacrol, Inhibit HIV-1 Fusion into Target Cells.

Oregano essential oil has long been known for its health-promoting benefits. Here, we report its activity against viral replication. Oregano oil was found to specifically inhibit lentiviruses, such as human and simian immunodeficiency viruses (HIV and SIV), irrespective of virus tropism, but not hepatitis C virus, adenovirus 5 (ADV5), Zika virus, and influenza (H1N1) virus. Oregano oil's most abundant components, carvacrol and its isomer, thymol, were shown to block virus-target cell fusion while not perturbing other stages of the virus life cycle. We detected changes in virus particle density, suggesting that cholesterol depletion from the HIV-1 envelope membrane reduces virus entry. Furthermore, infection was rescued by adding exogenous cholesterol. The evolution of viral resistance to carvacrol supported this mechanism of action with the identification of mutations in the viral gp41 fusion protein that counteracted cholesterol depletion. In addition, resistance to carvacrol emerged later than typically observed for other clinically used drugs, strengthening its antiviral potential. Structure-activity relationship studies revealed key motifs of carvacrol and thymol required for HIV neutralization and identified previously unknown active analogs. Carvacrol was also shown to additively cooperate with antiretroviral therapy. In sum, oregano oil and improved carvacrol and thymol analogs could be considered to supplement current HIV therapeutics.IMPORTANCE Oregano essential oil has multiple benefits in traditional medicine, cosmetics, and food industries. Carvacrol and its analog, thymol, are well-described components of oregano oil. Here, we show that these compounds inhibit HIV-target cell fusion independently of viral tropism. Our results suggest that carvacrol and thymol alter the cholesterol content of the viral membrane, blocking HIV-1 entry into the target cell. Resistance to carvacrol has selected for viruses with mutations in the viral envelope glycoprotein, gp41. This protein is known for its interaction with cholesterol present in membrane lipid rafts. Together, these results demonstrate the potential of therapies targeting the viral envelope membrane, and oregano oil is a safe supplement to antiretrovirals, potentially delaying disease progression and resistance development.

Potent suppression of HIV-1 cell attachment by Kudzu root extract.

There is a constant need to improve antiretrovirals against HIV since therapy is limited by cost, side effects and the emergence of drug resistance. Kudzu is a climbing vine from which the root extract (Pueraria lobata), rich in isoflavones and saponins, has long been used in traditional Chinese medicine for a variety of purposes, from weight loss to alcoholism prevention. Here we show that Kudzu root extract significantly inhibits HIV-1 entry into cell lines, primary human CD4+T lymphocytes and macrophages, without cell-associated toxicity. Specifically, Kudzu inhibits the initial attachment of the viral particle to the cell surface, a mechanism that depends on the envelope glycoprotein gp120 but is independent from the HIV-1 cell receptor CD4 and co-receptors CXCR4/CCR5. This activity seems selective to lentiviruses since Kudzu inhibits HIV-2 and simian immunodeficiency virus, but does not interfere with Hepatitis C, Influenza, Zika Brazil and adenovirus infection. Importantly, depending on the dose, Kudzu can act synergistically or additively with the current antiretroviral cocktails against HIV-1 and can block   viruses resistant to the fusion inhibitor Enfuvirtide. Together our results highlight Kudzu's root extract value as a supplement to current antiretroviral therapy against HIV.

Structure-function relationships of hirulog peptide interactions with thrombin.

Using hirudin as a model, a novel class of bivalent thrombin inhibitors has been designed and characterized (Maraganore et al. (1990) Biochemistry 29, 7095-7101). These peptides, designated 'hirulogs', interact with both thrombin's catalytic center and its anion-binding exosite for fibrinogen recognition. In order to investigate structure-activity relationships in hirulog peptides, a number of peptide and peptidomimetic derivatives with alterations in catalytic-site binding and anion-binding exosite binding moieties were prepared. Replacements or modifications in the catalytic site and exosite binding moieties were achieved with the consequences of maintaining or improving antithrombin activity. In addition to showing improved affinity for thrombin, some derivatives with Ki's in the sub-nanomolar range showed increased anticoagulant activities. These findings highlight the versatility of hirulog peptides in their bivalent interactions with thrombin.

A simple and efficient procedure for the synthesis of 5'-aminoalkyl oligodeoxynucleotides.

Synthetic deoxyoligonucleotides have been 5'-aminoalkylated at the end of step-wise synthesis on the polymer support. This was achieved through the activation of the 5'-hydroxyl group as its 5'-imidazolyl derivative using carbonyldiimidazole, which was subsequently displaced with hexamethylene diamine to yield the title compound. The alkyl carbamate linkage thus generated withstands the deprotection conditions used in oligonucleotide synthesis. Purification by gel electrophoresis and further derivatization at the 5'-amino group with N-hydroxysuccinimidobiotin is described.