Anti-MRSA activity of abietane diterpenes from Coleus blumei Benth.

Two heretofore uncharacterised abietane diterpenes, sincoetsin C (1) and 3-hydroxyspirocoleon 7-O-ß-D-glucoside (4), were isolated from a methanolic extract of Coleus blumei Benth. (Lamiaceae), along with the known compounds, scutellarioidone A (2) and spirocoleon 7-O-ß-D-glucoside (3) using chromatographic techniques. Their structures were determined by 1D and 2D nuclear magnetic resonance including HSQC, HMBC, COSY and NOESY experiments, mass spectrometry (HR-MS) and other spectroscopic methods (UV, IR). Their antibacterial activity against the reference strain of methicillin-resistant Staphylococcus aureus subsp. aureus CCM 4750 (MRSA) was evaluated using optical absorption to obtain quantitative information on their growth. All isolated compounds displayed anti-MRSA 4750 activity at the concentration of 512 µg/mL. Sincoetsin C (1) was the abietane diterpene most active against MRSA 4750, with a minimum inhibitory concentration of 128 µg/mL.

Phenylpropanoids and flavonoid from Helichrysum petiolare Hilliard & B. L. Burtt.

The phytochemical analysis of a  methanolic extract from Helichrysum petiolare Hilliard & B. L. (Asteraceae) confirmed the content of phenylpropanoids and flavonoids. Five secondary metabolites were isolated using preparative HPLC, namely coumarin scopolin (1), 3-chlorogenic acid (2), caffeic acid-hexose derivative (3), dicaffeoylquinic acid (5), and the flavonoid isoquercitrin (4). These compounds were identified from this species for the first time. Only dicaffeoylquinic acid was able to inhibit Escherichia coli CCM 7929 at the concertation of 512 μg mL-1 in a screening of antibacterial activity.

Natural Products-Derived Chemicals: Breaking Barriers to Novel Anti-HSV Drug Development.

Recently, the problem of viral infection, particularly the infection with herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), has dramatically increased and caused a significant challenge to public health due to the rising problem of drug resistance. The antiherpetic drug resistance crisis has been attributed to the overuse of these medications, as well as the lack of new drug development by the pharmaceutical industry due to reduced economic inducements and challenging regulatory requirements. Therefore, the development of novel antiviral drugs against HSV infections would be a step forward in improving global combat against these infections. The incorporation of biologically active natural products into anti-HSV drug development at the clinical level has gained limited attention to date. Thus, the search for new drugs from natural products that could enter clinical practice with lessened resistance, less undesirable effects, and various mechanisms of action is greatly needed to break the barriers to novel antiherpetic drug development, which, in turn, will pave the road towards the efficient and safe treatment of HSV infections. In this review, we aim to provide an up-to-date overview of the recent advances in natural antiherpetic agents. Additionally, this paper covers a large scale of phenolic compounds, alkaloids, terpenoids, polysaccharides, peptides, and other miscellaneous compounds derived from various sources of natural origin (plants, marine organisms, microbial sources, lichen species, insects, and mushrooms) with promising activities against HSV infections; these are in vitro and in vivo studies. This work also highlights bioactive natural products that could be used as templates for the further development of anti-HSV drugs at both animal and clinical levels, along with the potential mechanisms by which these compounds induce anti-HSV properties. Future insights into the development of these molecules as safe and effective natural anti-HSV drugs are also debated.

Prenylated Stilbenoids Affect Inflammation by Inhibiting the NF-κB/AP-1 Signaling Pathway and Cyclooxygenases and Lipoxygenase.

Stilbenoids are important components of foods (e.g., peanuts, grapes, various edible berries), beverages (wine, white tea), and medicinal plants. Many publications have described the anti-inflammatory potential of stilbenoids, including the widely known trans-resveratrol and its analogues. However, comparatively little information is available regarding the activity of their prenylated derivatives. One new prenylated stilbenoid (2) was isolated from Artocarpus altilis and characterized structurally based on 1D and 2D NMR analysis and HRMS. Three other prenylated stilbenoids were prepared synthetically (9-11). Their antiphlogistic potential was determined by testing them together with known natural prenylated stilbenoids from Macaranga siamensis and Artocarpus heterophyllus in both cell-free and cell assays. The inhibition of 5-lipoxygenase (5-LOX) was also shown by simulated molecular docking for the most active stilbenoids in order to elucidate the mode of interaction between these compounds and the enzyme. Their effects on the pro-inflammatory nuclear factor-κB (NF-κB) and the activator protein 1 (AP-1) signaling pathway were also analyzed. The THP1-XBlue-MD2-CD14 cell line was used as a model for determining their anti-inflammatory potential, and lipopolysaccharide (LPS) stimulation of Toll-like receptor 4 induced a signaling cascade leading to the activation of NF-κB/AP-1. The ability of prenylated stilbenoids to attenuate the production of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) was further evaluated using LPS-stimulated THP-1 macrophages.

Paeonia arietina and Paeonia kesrounansis bioactive constituents: NMR, LC-DAD-MS fingerprinting and in vitro assays.

Paeonia species have been valued for their ethnomedicinal uses in various countries and received much interest among the scientific community for their therapeutic properties, including anti-microbial, anti-inflammatory, anti-cancer, nephroprotective and hepatoprotective effects. The multiple phytotherapeutical applications of Paeonia species inspired us to establish the phytochemical fingerprint and to evaluate the biological properties of ethyl acetate, methanol, and aqueous extracts from the roots and aerial parts of two Paeonia species (P. arietina G. Anderson and P. kesrounansis Thiébaut). Phytoconstituents of P. arietina and P. kesrounansis extracts were analyzed using 1D and 2D NMR and LC-DAD-ESI-MS. The total content of phenolics (TPC) and flavonoids (TFC) in the extracts was also evaluated. The antioxidant activity was profiled using DPPH, ABTS, CUPRAC, FRAP, phosphomolybdenum, and metal chelation assays. Enzyme inhibitory properties were evaluated against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, α-amylase, and α-glucosidase. Phytochemical analysis of P. arietina and P. kesrounansis extracts showed the presence of galloyl esters of sugars, galloyl monoterpenes, and glycosylated flavonoids. The three solvent extracts presented different behavior in the bioassays. The highest antioxidant activity, tyrosinase and AChE inhibition were observed for the methanolic extract of the aerial parts of P. kesrounansis. In addition, the ethyl acetate extracts of the aerial parts of both plants were the most effective inhibitors of α-amylase. The highest BChE inhibition was observed for root methanolic extract of P. kesrounansis while the root ethyl acetate extract of P. arietina exerted the strongest inhibition of α-glucosidase. Methanol extract of P. kesrounansis aerial parts presented the highest TPC, while TFC was greatest in the corresponding extract of P. arietina. Our findings can be considered as a starting point for future studies to further validate the effectiveness and safety profiles of these plants in folk medicine.