Drug leads from the Kallawaya herbalists of Bolivia. 1. Background, rationale, protocol and anti-HIV activity

Anti-Human Immunodeficiency Virus-1 Property of Thai Herbal Extract Kerra™

Kerra™, a Thai traditional herbal medicine derived from the "Tak-Ka-Si-La Scripture" and composed of nine medicinal plants, has demonstrated potential antiviral properties against HIV. This study investigated the inhibitory effects of Kerra™ on HIV-1 reverse transcriptase (RT) and its ability to prevent pseudo-HIV viral infection in HEK293 cells. The results showed that Kerra™ extract achieved a 95.73 ± 4.24% relative inhibition of HIV-1 RT, with an IC50 value of 42.66 ± 8.74 µg/mL. Docking studies revealed that key phytochemicals in Kerra™, such as oleamide, formononetin, and biochanin A, interact with several residues in the RT non-nucleoside binding pocket, contributing to their inhibitory effects. Furthermore, Kerra™ was able to reduce pseudo-HIV infection in HEK293 cells at a concentration of 10 µg/mL, suggesting its potential as a supplementary treatment for HIV.

Ethnopharmacological Potential of Phytochemicals and Phytogenic Products against Human RNA Viral Diseases as Preventive Therapeutics

RNA viruses have been the most destructive due to their transmissibility and lack of control measures. Developments of vaccines for RNA viruses are very tough or almost impossible as viruses are highly mutable. For the last few decades, most of the epidemic and pandemic viral diseases have wreaked huge devastation with innumerable fatalities. To combat this threat to mankind, plant-derived novel antiviral products may contribute as reliable alternatives. They are assumed to be nontoxic, less hazardous, and safe compounds that have been in uses in the beginning of human civilization. In this growing COVID-19 pandemic, the present review amalgamates and depicts the role of various plant products in curing viral diseases in humans.

Evaluation of Wound Healing Activity of Salvia haenkei Hydroalcoholic Aerial Part Extract on in vitro and in vivo Experimental Models

Purpose

The aim of the present study was to evaluate the potential wound healing activity of the hydroalcoholic extract of Salvia haenkei on in vitro and in vivo experimental models.

Materials and Methods

Preliminary analytical characterization of the hydroalcoholic extract of Salvia haenkei was made by reversed-phase high performance liquid chromatography (RP-HPLC) that permitted identification of a qualitative fingerprint of the extract of aerial parts. The wound healing activity of the hydroalcoholic extract of Salvia haenkei was evaluated in vitro by the scratch assay on human dermal fibroblasts and human epidermal keratinocytes and in vivo by standardized mouse excisional splinting model. Real-time PCR (RT-PCR) experiments were performed to analyze gene expression levels of inflammatory markers.

Results

The scratch assay tests showed that the treatment with the hydroalcoholic extract of Salvia haenkei did not induce an increase in the fibroblasts migration rate with respect to the positive control. Instead, the hydroalcoholic extract of Salvia haenkei was effective in improving the wound closure rate on keratinocyte cell cultures with an almost total invasion of the scratch after 48 h of treatment; whereas the positive control, at the same time point, showed only a 67% reduction of the wound size. In vivo experiments showed that the groups treated with the extract of Salvia haenkei completely re-epithelized the wound in 2.7 days, a timing that was comparable with the action of the positive control that took only 2.1 days. Gene expression analysis showed that Salvia haenkei positively regulated the signaling pathway of the nuclear factor-κB (NF-κB) transcription factor.

Conclusion

The results suggested that the hydroalcoholic extract of Salvia haenkei induced a clear wound healing effect.

Structure-Activity-Relationship and Mechanistic Insights for Anti-HIV Natural Products

Acquired Immunodeficiency Syndrome (AIDS), which chiefly originatesfroma retrovirus named Human Immunodeficiency Virus (HIV), has impacted about 70 million people worldwide. Even though several advances have been made in the field of antiretroviral combination therapy, HIV is still responsible for a considerable number of deaths in Africa. The current antiretroviral therapies have achieved success in providing instant HIV suppression but with countless undesirable adverse effects. Presently, the biodiversity of the plant kingdom is being explored by several researchers for the discovery of potent anti-HIV drugs with different mechanisms of action. The primary challenge is to afford a treatment that is free from any sort of risk of drug resistance and serious side effects. Hence, there is a strong demand to evaluate drugs derived from plants as well as their derivatives. Several plants, such as Andrographis paniculata, Dioscorea bulbifera, Aegle marmelos, Wistaria floribunda, Lindera chunii, Xanthoceras sorbifolia and others have displayed significant anti-HIV activity. Here, weattempt to summarize the main results, which focus on the structures of most potent plant-based natural products having anti-HIV activity along with their mechanisms of action and IC50 values, structure-activity-relationships and important key findings.

Medicinal Plants Used in the Treatment of Human Immunodeficiency Virus

Since the beginning of the epidemic, human immunodeficiency virus (HIV) has infected around 70 million people worldwide, most of whom reside is sub-Saharan Africa. There have been very promising developments in the treatment of HIV with anti-retroviral drug cocktails. However, drug resistance to anti-HIV drugs is emerging, and many people infected with HIV have adverse reactions or do not have ready access to currently available HIV chemotherapies. Thus, there is a need to discover new anti-HIV agents to supplement our current arsenal of anti-HIV drugs and to provide therapeutic options for populations with limited resources or access to currently efficacious chemotherapies. Plant-derived natural products continue to serve as a reservoir for the discovery of new medicines, including anti-HIV agents. This review presents a survey of plants that have shown anti-HIV activity, both in vitro and in vivo.

Changing markets - Medicinal plants in the markets of La Paz and El Alto, Bolivia

ETHNOPHARMACOLOGICAL RELEVANCE

Given the importance of local markets as a source of medicinal plants for both healers and the population, literature on market flows and the value of the plant material traded is rather scarce. This stands in contrast to wealth of available information for other components of Bolivian ethnobotany. The present study attempts to remedy this situation by providing a detailed inventory of medicinal plant markets in the La Paz-El Alto metropolitan area, hypothesizing that both species composition, and medicinal applications, have changed considerably over time.

MATERIALS AND METHODS

From October 2013-October 2015 semi-structured interviews were conducted with 39 plant vendors between October 2013 and October 2015 in the Mercado Rodriguez, Mercado Calle Santa Cruz, Mercado Cohoni, Mercado Cota Cota, and Mercado Seguencoma and Mercado El Alto in order to elucidate more details on plant usage and provenance. The results of the present study were then compared to previous inventories of medicinal plants in La Paz and El Alto studies to elucidate changes over time and impact of interview techniques.

RESULTS

In this study we encountered 163 plant species belonging to 127 genera and 58 families. In addition, 17 species could not be identified. This species richness is considerably higher than that reported in previous studies (2005, 129 species of 55 families; 2015, 94 identified species). While the overall distribution of illness categories is in line with older reports the number of species used per application, as well as the applications per species, were much higher in the present study. Overall, informant consensus was relatively low, which might be explained by the large number of new species that have entered the local pharmacopoeia in the last decade, although some species might simply have been missed by previous studies. In course of the present study it became apparent that even well known species might often be replaced by other apparently similar but botanically unrelated species due to environmental and market forces CONCLUSIONS: The present study indicated that, while the floristic composition of markets in the La Paz metropolitan area remained relatively constant over the last decade, with this inventory adding about 20% of species to previous studies, the number of indications for which certain species were used increased tremendously, and that profound differences exist even between markets in close proximity. The dramatic increase in previously not used species used per indication might pose serious risks for consumers. We found serious problems due to species replacements. Even plants that have a well established vernacular name, and are easily recognizable botanically, can be replaced by other species that can pose a serious health risk. Vendor education and stringent identification of the material sold in public markets are clearly needed.

Isolation of cytotoxic diterpenoids from the Chilean medicinal plant Azorella compacta Phil from the Atacama Desert by high-speed counter-current chromatography

BACKGROUND

Azorella compacta (Apiaceae) is a native Chilean cushion shrub which produces a resin containing mulinane and azorellane diterpenoids. This plant has been used since pre-Colombian times to treat inflammation and dental neuralgias. In this work the first preparative fractionation of diterpenoids present in this plant by means of high-speed counter-current chromatography (HSCCC) was applied, and cytotoxic effects of the isolated compounds were evaluated for the first time against a panel of MCF7 cells.

RESULTS

The major compounds isolated were identified by means of spectroscopy as azorellanol, 13α, 14α-dihydroxymulin-11-en-20-oic acid, mulinolic acid, mulin-11,13-dien-20-oic acid, 17-acetoxy-mulin-11,13-dien-20 oic acid, and 17-acetoxy-mulinic acid (compounds 7, 9-11 and 13, respectively), and four minor diterpenoids [7-deacetyl-azorellanol (6), 13-epi-azorellanol, 7-acetoxy-mulin-9,12-diene, and 17-acetoxy-mulin-11,13-dien-20-oic acid (compounds 4, 8 and 12)], together with three new minor diterpenoids: 13β,14β-dihydroxymulin-11-en-20-oic acid (1), 13-epiazorellanone (2) and 13-epi-7-deacetyl-azorellanol (3) were identified. Besides, compounds 4, 6, 7, 8 and 11 displayed good cytotoxic activity (less than 50% cell viability at 100 µM). Among them, compound 7, an acetylated azorellane, was the most active.

CONCLUSIONS

HSCCC allowed the isolation of 13 diterpenoids present in A. compacta. Three compounds are reported for the first time. Isolated azorellanes are more potent cytotoxic agents than are mulinanes. © 2015 Society of Chemical Industry.

Structure and antimicrobial activity of phloroglucinol derivatives from Achyrocline satureioides

The new prenylated phloroglucinol α-pyrones 1-3 and the new dibenzofuran 4, together with the known 23-methyl-6-O-demethylauricepyrone (5), achyrofuran (6), and 5,7-dihydroxy-3,8-dimethoxyflavone (gnaphaliin A), were isolated from the aerial parts of Achyrocline satureioides. Their structures were determined by 1D and 2D NMR spectroscopic studies, while the absolute configuration of the sole stereogenic center of 1 was established by vibrational circular dichroism measurements in comparison to density functional theory calculated data. The same (S) absolute configuration of the α-methylbutyryl chain attached to the phloroglucinol nucleus was assumed for compounds 2-6 based on biogenetic considerations. Derivatives 7-16 were prepared from 1 and 5, and the antimicrobial activities of the isolated metabolites and some of the semisynthetic derivatives against a selected panel of Gram-positive and Gram-negative bacteria, as well as a set of yeast molds, were determined.

Mutagenesis of Lysines 156 and 159 in Human Immunodeficiency Virus Type 1 Integrase (IN) Reveals Differential Interactions between these Residues and Different IN Inhibitors

Human immunodeficiency virus (HIV) type 1 integrase (IN) active site, and viral DNA-binding residues K156 and K159 are predicted to interact both with strand transfer-selective IN inhibitors (STI), e.g. L-731,988, Elvitegravir (EVG), and the FDA-approved IN inhibitor, Raltegravir (RGV), and strand transfer non-selective inhibitors, e.g. dicaffeoyltartaric acids (DCTAs), e.g. L-chicoric acid (L-CA). To test posited roles for these two lysine residues in inhibitor action we assayed the potency of L-CA and several STI against a panel of K156 and K159 mutants. Mutagenesis of K156 conferred resistance to L-CA and mutagenesis of either K156 or K159 conferred resistance to STI indicating that the cationic charge at these two viral DNA-binding residues is important for inhibitor potency. IN K156N, a reported polymorphism associated with resistance to RGV, conferred resistance to L-CA and STI as well. To investigate the apparent preference L-CA exhibits for interactions with K156, we assayed the potency of several hybrid inhibitors containing combinations of DCTA and STI pharmacophores against recombinant IN K156A or K159A. Although K156A conferred resistance to diketo acid-branched bis-catechol hybrid inhibitors, neither K156A nor K159A conferred resistance to their monocatechol counterparts, suggesting that bis-catechol moieties direct DCTAs toward K156. In contrast, STI were more promiscuous in their interaction with K156 and K159. Taken together, the results of this study indicate that DCTAs interact with IN in a manner different than that of STI and suggest that DCTAs are an attractive candidate chemotype for development into drugs potent against STI-resistant IN.

A new mulinane diterpenoid from the cushion shrub Azorella compacta growing in Perú

Background:

Azorella compacta is a rare yellow-green compact resinous cushion shrub growing from the high Andes of southern Perú to northwestern Argentina, and which is a producer of biologically active and unique diterpenoids.

Objective:

This study investigated the secondary metabolites present in a Peruvian sample of Azorella compacta and the evaluation of gastroprotective activity of the isolated compounds in a gastric- induced ulcer model in mice.

Material and Methods:

Six secondary metabolites (diterpenoids 1-6) present in the dichloromethane (DCM) extract of A. compacta growing in Perú were isolated by a combination of Sephadex LH-20 permeation and silica gel chromatography and their chemical structures were elucidated by spectroscopic methods (NMR) and molecular modeling. The gastroprotective activity of the new compound 1 was evaluated on the HCl/EtOH-induced gastric lesion model in mice and compared to the activity showed by the known compounds.

Results:

A new mulinane diterpene along with five known diterpenoids have been isolated from a Peruvian sample of A. compacta and the gastroprotective results show that compound 1 is less active than the other known mulinane diterpenoids isolated.

Conclusions:

A. compacta growing in Perú showed the presence of the new mulinane 1, which was poorly active in the HCl/EtOH-induced gastric lesion model in mice. Indeed, the activity was lower than other diterpenoids (2-6) showing an oxygenated function at C-16 or/and C-20, which confirm the role of an oxygenated group (OH or carboxylic acid) for the gastroprotective activity of mulinane compounds.

A symmetric region of the HIV-1 integrase dimerization interface is essential for viral replication

HIV-1 integrase (IN) is an important target for contemporary antiretroviral drug design research. Historically, efforts at inactivating the enzyme have focused upon blocking its active site. However, it has become apparent that new classes of allosteric inhibitors will be necessary to advance the antiretroviral field in light of the emergence of viral strains resistant to contemporary clinically used IN drugs. In this study we have characterized the importance of a close network of IN residues, distant from the active site, as important for the obligatory multimerization of the enzyme and viral replication as a whole. Specifically, we have determined that the configuration of six residues within a highly symmetrical region at the IN dimerization interface, composed of a four-tiered aromatic interaction flanked by two salt bridges, significantly contributes to proper HIV-1 replication. Additionally, we have utilized a quantitative luminescence assay to examine IN oligomerization and have determined that there is a very low tolerance for amino acid substitutions along this region. Even conservative residue substitutions negatively impacted IN multimerization, resulting in an inactive viral enzyme and a non-replicative virus. We have shown that there is a very low tolerance for amino acid variation at the symmetrical dimeric interface region characterized in this study, and therefore drugs designed to target the amino acid network detailed here could be expected to yield a significantly reduced number of drug-resistant escape mutations compared to contemporary clinically-evaluated antiretrovirals.

Evaluation of antiviral activity of aqueous extracts from Achyrocline satureioides against Western equine encephalitis virus

Achyrocline satureioides (Asteraceae) is a medicinal plant traditionally used in Argentina for the treatment of intestinal infections and various digestive disorders. Its infusion is widely utilised for respiratory problems and viral infections. The objective of this study was to investigate cytotoxicity, virucidal and antiviral properties of the cold aqueous extract (CAE) and hot aqueous extract (HAE) of this plant against Western equine encephalitis virus (WEEV). Cytotoxicity in Vero cells was evaluated by maximum non-cytotoxic concentration (MNCC), neutral red (NR) uptake and MTT reduction methods. To study the antiviral activity of aqueous extracts, plaque reduction assay was performed after pre-treatment of host cells, adsorption, penetration and post-penetration of the virus. Extracellular virus inactivation was also analysed by the same method. Extracts showed strong inhibitory activity after virus penetration with selective index values of 32 (NR) and 63.3 (MTT) for the CAE, and 16.2 (NR) and 24.3 (MTT) for the HAE. Both extracts exhibited virucidal action with lower efficacy than their antiviral properties. The present results demonstrate that aqueous extracts of A. satureioides are active against WEEV. Further studies are needed in order to identify which compounds could be responsible for this effect, and how they exert antiviral action.

Anti-tuberculosis Compounds from Mallotus philippinensis

Bioassay-directed fractionation of the organic extract of Mallotus philippinensis gave five compounds (1-5), the most active of which against Mycobacterium tuberculosis was a new compound, 8-cinnamoyl-5,7-dihydroxy-2,2-dimethyl-6-geranylchromene (1) for which the name mallotophilippen F is suggested. Compound (2), 8-cinnamoyl-2,2-dimethyl-7-hydroxy-5-methoxychromene, was isolated from a natural source for the first time, while the remaining three compounds, rottlerin (3), isoallorottlerin=isorottlerin (4) and the so-called “red compound,” 8-cinnamoyl-5,7-dihydroxy-2,2,6-trimethylchromene (5), had been isolated previously from this plant. All compounds were identified by analysis of their spectra including 2D-NMR, which was used to correct the literature NMR spectral assignments of compounds 2-4. The C-13 NMR of 5 is reported for the first time.

Anti-tuberculosis Compounds from two Bolivian Medicinal Plants, Senecio Mathewsii and Usnea Florida

Bioassay-directed fractionation of the organic extract of Senecio mathewsii gave four compounds with anti-TB activity: werneria chromene (1), capillarol (2), werneria chromanone (3) and plicatin B (4). All of these are new to the genus Senecio and one of these, werneria chromanone (3), was isolated from a natural source for the first time. With the aid of 2D NMR, revised (1) or new (2–4) spectral assignments were made. Similarly, the major anti-TB activity of Usnea florida was shown to be solely due to usnic acid.

Preliminary mapping of a putative inhibitor-binding pocket for human immunodeficiency virus type 1 integrase inhibitors

Molecular modeling studies have identified a putative human immunodeficiency virus (HIV) integrase (IN) inhibitor-binding pocket for l-chicoric acid (l-CA) and other inhibitors of IN (C. A. Sotriffer, H. Ni, and A. McCammon, J. Med. Chem. 43:4109-4117, 2000). By using site-directed mutagenesis of several amino acid residues identified by modeling studies, a common inhibitor-binding pocket on IN was confirmed for l-CA and the diketo acid L-731,988. Specifically, the single mutations E92K, Q148A, K156A, K156R, G140S, and G149S, as well as the double mutations C65S-K156N and H67D-G140A were evaluated for their effects on enzymatic activity and inhibitor susceptibility. Each recombinant IN was attenuated for 3'-end processing and strand transfer activities. Most proteins were also attenuated for disintegration; the IN that contained K156R and C65S-K156N, however, displayed disintegration activity similar to that of IN from HIV(NL4-3). All mutant IN proteins demonstrated decreased susceptibility to l-CA, while all mutant proteins except E92K and K156R demonstrated resistance to L-731,988. These data validate the computer modeling data and demonstrate that l-CA and L-731,988 share an overlapping inhibitor-binding pocket that involves amino acids Q148, C65, and H67. The resistance studies confirm that L-731,988 fills one-half of the inhibitor-binding pocket and binds to Q148 but excludes E92, while l-CA fills the entire binding groove and thus interacts with E92. These results provide "wet laboratory" evidence that molecular models of the HIV IN inhibitor-binding pocket can be used for drug discovery.

Screening of Australian medicinal plants for antiviral activity

Extracts of 40 different plant species used in the traditional medicine of the Australian Aboriginal people have been investigated for antiviral activity. The extracts have been tested for activity against one DNA virus, human cytomegalovirus (HCMV) and two RNA viruses, Ross River virus (RRV) and poliovirus type 1, at non-cytotoxic concentrations. The most active extracts were the aerial parts of Pterocaulon sphacelatum (Asteraceae) and roots of Dianella longifolia var. grandis (Liliaceae), which inhibited poliovirus at concentrations of 52 and 250 microg/ml, respectively. The extracts of Euphorbia australis (Euphorbiaceae) and Scaevola spinescens (Goodeniaceae) were the most active against HCMV. Extracts of Eremophila latrobei subsp. glabra (Myoporaceae) and Pittosporum phylliraeoides var. microcarpa (Pittosporaceae) exhibited antiviral activity against RRV.