HIV-Inhibitory Gallotannins fromLepidobotrys staudtii

Emerging paradigms of viral diseases and paramount role of natural resources as antiviral agents

In the current scenario, the increasing prevalence of diverse microbial infections as well as emergence and re-emergence of viral epidemics with high morbidity and mortality rates are major public health threat. Despite the persistent production of antiviral drugs and vaccines in the global market, viruses still remain as one of the leading causes of deadly human diseases. Effective control of viral diseases, particularly Zika virus disease, Nipah virus disease, Severe acute respiratory syndrome, Coronavirus disease, Herpes simplex virus infection, Acquired immunodeficiency syndrome, and Ebola virus disease remain promising goal amidst the mutating viral strains. Current trends in the development of antiviral drugs focus solely on testing novel drugs or repurposing drugs against potential targets of the viruses. Compared to synthetic drugs, medicines from natural resources offer less side-effect to humans and are often cost-effective in the productivity approaches. This review intends not only to emphasize on the major viral disease outbreaks in the past few decades and but also explores the potentialities of natural substances as antiviral traits to combat viral pathogens. Here, we spotlighted a comprehensive overview of antiviral components present in varied natural sources, including plants, fungi, and microorganisms in order to identify potent antiviral agents for developing alternative therapy in future.

A new cineol derivative, polyphenols and norterpenoids from Saharan myrtle tea (Myrtus nivellei): Isolation, structure determination, quantitative determination and antioxidant activity

The phytochemical profile of decoction and infusion, obtained from the dried leaves of M. nivellei, consumed as tea in Saharan region, was characterized by UHPLC-PDA-HRMS. Fourteen compounds were characterized and, to confirm the proposed structures a preparative procedure followed by NMR spectroscopy was applied. Compound 3 (2-hydroxy-1,8-cineole disaccharide) was a never reported whereas a bicyclic monoterpenoid glucoside (2), two ionol glucosides (1 and 12), a tri-galloylquinic acid (4), two flavonol glycosides (5 and 9), and a tetra-galloylglucose (7), were reported in Myrtus spp. for the first time. Five flavonol O-glycosides (6, 8, 10-11, and 14) togheter a flavonol (13) were also identified. Quantitative determination of phenolic constituents from decoction and infusion has been performed by HPLC-UV-PDA. The phenolic content was found to be 150.5 and 102.6mg/g in decoction and infusion corresponding to 73.8 and 23.6mg/100mL of a single tea cup, respectively. Myricetin 3-O-β-d-(6″-galloyl)glucopyranoside (5), isomyricitrin (6) and myricitrin (8) were the compounds present in the highest concentration. The free-radical scavenging activities of teas and isolated compounds was measured by the DPPH assay and compared with the values of other commonly used herbal teas (green and black teas). Decoction displayed higher potency in scavenging free-radicals than the infusion and green and black teas.

HIV-1 ribonuclease H inhibitory phenolic glycosides from Eugenia hyemalis

Three new galloyl arbutins, hyemalosides A-C (1-3), along with nine known compounds were isolated from the evergreen tree Eugenia hyemalis. The structures of compounds 1-3 were determined by analysis of NMR and MS data. Compounds 1-3 inhibited HIV-1 RNase H in vitro with IC50 values of 1.46, >18, and 1.19 microM, respectively. However, in a XTT-based cell viability assay using the human T-cell line CEM-SS infected with HIV-1 RT, none of the compounds inhibited the cytopathic effect of HIV-1 infection at the highest dose tested (20 microg/mL).

Profiling and characterization by LC-MSn of the galloylquinic acids of green tea, tara tannin, and tannic acid

Green tea, tara tannin, and tannic acid have been profiled for their contents of galloylquinic acids using LC-MS8. These procedures have provided evidence for the first observation of (i) 1-galloylquinic acid (11), 1,3,5-trigalloylquinic acid (22), 4-(digalloyl)quinic acid (28), 5-(digalloyl)quinic acid (29), and either 3-galloyl-5-(digalloyl)quinic acid (32) or 3-(digalloyl)-5-galloylquinic acid (33) from any source; (ii) 4-galloyl-5-(digalloyl)quinic acid (34), 5-galloyl-4-(digalloyl)quinic acid (35), 3-(digalloyl)-4,5-digalloylquinic acid (41), 4-(digalloyl)-3,5-digalloylquinic acid (40), 5-(digalloyl)-3,4-digalloylquinic acid (39), and 1,3,4-trigalloylquinic acid (21) from tara tannin; and (iii) 3-galloylquinic acid (12) and 4-galloylquinic acid (14) from green tea. The first mass spectrometric fragmentation data are reported for galloylquinic acids containing between five and eight gallic acid residues. For each of these mass ranges at least two isomers based on the 1,3,4,5-tetragalloylquinic acid core (25) and at least three based on the 3,4,5-trigalloylquinic acid core (24) were observed. Methanolysis of tara tannin yielded methyl gallate, methyl digallate, and methyl trigallate, demonstrating that some of these galloylquinic acids contained at least one side chain of up to four galloyl residues.

An overview of the biology of the desiccation-tolerant resurrection plant Myrothamnus flabellifolia

BACKGROUND

Myrothamnus flabellifolia is unique as the only woody resurrection plant. It is an important plant in southern Africa because of its widespread occurrence and usage in African medicine and traditional culture. Many reports have investigated facets of its biology and the mechanisms associated with its desiccation tolerance.

SCOPE

The general biology of the woody resurrection plant Myrothamnus flabellifolia is reviewed. The review focuses on the geography and ecology, systematic placement, evolution, morphology and reproductive ecology of M. flabellifolia as well as the wood anatomy and re-filling mechanism. In addition, the desiccation tolerance, ethnobotanical importance and medicinal properties of the plant are reviewed. Also, future research avenues are suggested, in particular the necessity to research the biogeography and systematics of the species and the role of the polyphenols present, as well as the molecular basis of the plant's desiccation tolerance.

Liquid chromatography/electrospray ionization tandem mass spectrometry profiling of compounds from the infusion of Byrsonima fagifolia Niedenzu

A rapid analytical approach suitable to achieve a comprehensive characterization of the compounds present in the infusion prepared from the leaves of Byrsonima fagifolia Niedenzu (Malpighiaceae), a Brazilian plant used as an infusion to treat gastric disorders, was developed. The method was based on high-performance liquid chromatography coupled to electrospray negative ionisation multistage ion trap mass spectrometry (HPLC/ESI-ITMSn). The main ions in the ESI-ITMS spectra were attributed to a quinic acid core containing from one to five galloyl units. Quercetin derivatives containing one and two sugar moieties as well as galloyl esterification were also detected. These results indicated that HPLC/ESI-ITMSn is easily applicable to infusions of this plant and allows the rapid and direct identification of these compounds in crude plant extracts.

The predominant polyphenol in the leaves of the resurrection plant Myrothamnus flabellifolius, 3,4,5 tri-O-galloylquinic acid, protects membranes against desiccation and free radical-induced oxidation

The predominant (>90%) low-molecular-mass polyphenol was isolated from the leaves of the resurrection plant Myrothamnus flabellifolius and identified to be 3,4,5 tri-O-galloylquinic acid using 1H and 13C one- and two-dimensional NMR spectroscopy. The structure was confirmed by mass spectrometric analysis. This compound was present at high concentrations, 44% (by weight) in hydrated leaves and 74% (by weight) in dehydrated leaves. Electron microscopy of leaf material fixed with glutaraldehyde and caffeine demonstrated that the polyphenols were localized in large vacuoles in both hydrated and dehydrated leaves. 3,4,5 Tri-O-galloylquinic acid was shown to stabilize an artificial membrane system, liposomes, against desiccation if the polyphenol concentration was between 1 and 2 microg/mug phospholipid. The phase transition of these liposomes observed at 46 degrees C was markedly diminished by the presence of 3,4,5 tri-O-galloylquinic acid, suggesting that the presence of the polyphenol maintained the membranes in the liquid crystalline phase at physiological temperatures. 3,4,5 Tri-O-galloylquinic acid was also shown to protect linoleic acid against free radical-induced oxidation.

Herbal medicines for sexually transmitted diseases and AIDS

Sexually transmitted diseases (STDs) and acquired immunodeficiency syndrome (AIDS) are gaining significant importance at present due to rapid spread of the diseases, high cost of treatment, and the increased risk of transmission of other STDs and AIDS. Current therapies available for symptomatic treatment of STDs and AIDS are quite expensive beyond the reach of common man and are associated with emergence of drug resistance. Many patients of STDs and AIDS are seeking help from alternative systems of medicines such as Unani, Chinese, Ayurvedic, naturopathy, and homeopathy. Since a long time, medicinal plants have been used for the treatment of many infectious diseases without any scientific evidence. At present there is more emphasis on determining the scientific evidence and rationalization of the use of these preparations. Research is in progress to identify plants and their active principles possessing activity against sexually transmitted pathogens including human immunodeficiency virus (HIV) with an objective of providing an effective approach for prevention of transmission and treatment of these diseases. In the present review, plants reported to possess activity or used in traditional systems of medicine for prevention and treatment of STDs including AIDS, herbal formulations for vaginal application, and topical microbicides from herbal origin, have been discussed.

Natural product-based anti-HIV drug discovery and development facilitated by the NCI developmental therapeutics program

During the decade 1987-1996, the Developmental Therapeutics Program (DTP) of the National Cancer Institute (NCI) provided infrastructure support for both intramural and extramural anti-HIV (human immunodeficiency virus) drug discovery research and development. This retrospective review describes some of the anti-HIV lead discovery and development that took place under DTP auspices or which was substantially facilitated by resources made available through the DTP. Examples highlighted include leads identified through the initial screening of pure natural product derived compounds and those derived from bioassay-guided fractionation of crude natural product extracts, and these are classified according to the mechanism of action targeting the critical steps within the replication cycle of HIV.