Amazonian medicinal plants efficiently inactivate Herpes and Chikungunya viruses.

The Amazonian species investigated in this research are commonly utilized for their anti-inflammatory properties and their potential against various diseases. However, there is a lack of scientifically supported information validating their biological activities. In this study, a total of seventeen ethanolic or aqueous extracts derived from eight Amazonian medicinal plants were evaluated for their activity against Herpes Simplex type 1 (HSV-1) and Chikungunya viruses (CHIKV). Cytotoxicity was assessed using the sulforhodamine B method, and the antiviral potential was determined through a plaque number reduction assay. Virucidal tests were conducted according to EN 14476 standards for the most potent extracts. Additionally, the chemical composition of the most active extracts was investigated. Notably, the LMLE10, LMBA11, MEBE13, and VABE17 extracts exhibited significant activity against CHIKV and the non-acyclovir-resistant strain of HSV-1 (KOS) (SI > 9). The MEBE13 extract demonstrated unique inhibition against the acyclovir-resistant strain of HSV-1 (29-R). Virucidal assays indicated a higher level of virucidal activity compared to their antiviral activity. Moreover, the virucidal capacity of the most active extracts was sustained when tested in the presence of protein solutions against HSV-1 (KOS). In the application of EN 14476 against HSV-1 (KOS), the LMBA11 extract achieved a 99.9% inhibition rate, while the VABE17 extract reached a 90% inhibition rate. This study contributes to the understanding of medicinal species native to the Brazilian Amazon, revealing their potential in combating viral infections that have plagued humanity for centuries (HSV-1) or currently lack specific therapeutic interventions (CHIKV).

Antimicrobial Prenylated Isoflavones from the Leaves of the Amazonian Medicinal Plant Vatairea guianensis Aubl.

Vatairea guianenis Aubl. (Fabaceae) is an Amazonian medicinal plant species traditionally used for treating skin diseases. In an initial screening, a V. guianensis leaf extract and its subextracts showed antibacterial and antifungal activities. The EtOAc subextract was selected for chemical workup and afforded five known (1-4 and 8) and six undescribed isoflavones, vatairenones C-H (5-7 and 9-11). All isoflavones are prenylated in position C-8, displaying either chain-prenylated (1-7) or ring-closed forms (8-11). The most bioactive compound (3) exhibited in vitro activity against clinically relevant bacteria and fungi with IC50 values ranging from 6.8 to 26.9 µM. Due to its broad antimicrobial activity and low general toxicity, compound 3 is a potential lead compound for structural modifications. The results of the present study support the ethnomedicinal use of V. guianensis in the treatment of dermatological disorders. 1H NMR spectra of some of the isolated compounds showed intricate signal patterns, which might explain repeated errors in assigning the correct structure of the isoflavonoid B-ring in the literature and which we resolved by higher order spectra simulations.

Chemical and Biological Evaluation of Amazonian Medicinal Plant Vouacapoua americana Aubl.

Vouacapoua americana (Fabaceae) is an economically important tree in the Amazon region and used for its highly resistant heartwood as well as for medicinal purposes. Despite its frequent use, phytochemical investigations have been limited and rather focused on ecological properties than on its pharmacological potential. In this study, we investigated the phytochemistry and bioactivity of V. americana stem bark extract and its constituents to identify eventual lead structures for further drug development. Applying hydrodistillation and subsequent GC-MS analysis, we investigated the composition of the essential oil and identified the 15 most abundant components. Moreover, the diterpenoids deacetylchagresnone (1), cassa-13(14),15-dien-oic acid (2), isoneocaesalpin H (3), (+)-vouacapenic acid (4), and (+)-methyl vouacapenate (5) were isolated from the stem bark, with compounds 2 and 4 showing pronounced effects on Methicillin-resistant Staphylococcus aureus and Enterococcus faecium, respectively. During the structure elucidation of deacetylchagresnone (1), which was isolated from a natural source for the first time, we detected inconsistencies regarding the configuration of the cyclopropane ring. Thus, the structure was revised for both deacetylchagresnone (1) and the previously isolated chagresnone. Following our works on Copaifera reticulata and Vatairea guianensis, the results of this study further contribute to the knowledge of Amazonian medicinal plants.

Viral Genome Integration into the Host Cell Genome: A Double Edged-Sword.

Genetic information exchange between virus and host cells apparently seems to be detrimental, as pluricellular organisms could develop diseases. Nevertheless, during billion years long evolutionary processes, the cell's genome revealed a mosaic of viral genomes or gene segments, giving rise to speculations that the genome of any cell was constructed and shaped by the invasion of virus genomes. But it could also be interpreted that the cellular genome is the source of autonomous gene segments that escaped from the cells, at some conditions, as a threat to the cell's survival. Quite commonly, oncogenic viruses integrate their genome in the host cell genome or interact in their episomal form. Some of these viruses cause lytic infection alternated with latent and persistent infection, leading to chronic inflammation, ultimately resulting in autoimmune diseases and cancer. Rarely, but potentially occurring, the genome of non-oncogenic RNA viruses could gain access to the cell nucleus, and eventually integrate their gene segments or genome in the host chromosome as it has been postulated for the current agent of the Corona Virus Disease 2019 (COVID-19), the Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2). Rather than re-infection, SARS-CoV-2 gene activation, from host chromosome integrated material, would explain the detection of virus gene segments as in viremia. Therefore, viral capsids or solely viral gene segments, actively and selectively transported to the cell nucleus, could be found taking into account the exuberant virome reaching the cell nucleus to perform their replicative cycle. So, would the integration of unconventional reverse transcribed viral RNA of SARS-CoV-2, and of other RNA viruses, as the Bornaviruses, lead to the production of transcripts and proteins inducing antigenemia and stimulating constant immune response, or else would result in the excessive activation of neighboring cellular genes with pathogenic role to the host cell?