Meroterpenoids are secondary metabolites formed due to mixed biosynthetic pathways which are produced in part from a terpenoid co-substrate. These mixed biosynthetically hybrid compounds are widely produced by bacteria, algae, plants, and animals. Notably amazing chemical diversity is generated among meroterpenoids via a combination of terpenoid scaffolds with polyketides, alkaloids, phenols, and amino acids. This review deals with the isolation, chemical diversity, and biological effects of 452 new meroterpenoids reported from natural sources from January 2016 to December 2020. Most of the meroterpenoids possess antimicrobial, cytotoxic, antioxidant, anti-inflammatory, antiviral, enzyme inhibitory, and immunosupressive effects.

No abstract

No abstract

No abstract

No abstract

Heliotropium is one of the most important plant genera to have conventional folklore importance, and hence is a potential source of bioactive compounds. Thus, the present study was designed to explore the therapeutic potential of Heliotropium crispum Desf., a relatively under-explored medicinal plant species. Methanolic extracts prepared from a whole plant of H. crispum were studied for phytochemical composition and possible in vitro and in silico biological properties. Antioxidant potential was assessed via six different assays, and enzyme inhibition potential against key clinical enzymes involved in neurodegenerative diseases (acetylcholinesterase (AChE) and butyrylcholinesterase (BChE)), diabetes (α-amylase and α-glucosidase), and skin problems (tyrosinase) was assayed. Phytochemical composition was established via determination of the total bioactive contents and reverse phase ultra-high performance liquid chromatography mass spectrometry (RP-UHPLC-MS) analysis. Chemical profiling revealed the tentative presence of 50 secondary metabolites. The plant extract exhibited significant inhibition against AChE and BChE enzymes, with values of 3.80 and 3.44 mg GALAE/g extract, respectively. Further, the extract displayed considerable free radical scavenging activity against DPPH and ABTS radicals, with potential values of 43.19 and 41.80 mg TE/g extract, respectively. In addition, the selected compounds were then docked against the tested enzymes, which have shown high inhibition affinity. To conclude, H. crispum was found to harbor bioactive compounds and showed potent biological activities which could be further explored for potential uses in nutraceutical and pharmaceutical industries, particularly as a neuroprotective agent.

The present work describes medicinal potential and secondary metabolic picture of the methanol extract (PP-M) of Polygonum plebeium R.Br. and its fractions; hexane (PP-H), ethyl acetate (PP-E) and water (PP-W). In total bioactive component estimation, highest contents of phenolic (89.38 � 0.27 mgGAE/g extract) and flavonoid (51.21 � 0.43 mgQE/g extract) were observed in PP-E, and the same fraction exhibited the highest antioxidant potential in DPPH (324.80 � 4.09 mgTE/g extract), ABTS (563.18 � 11.39 mgTE/g extract), CUPRAC (411.33 � 15.49 mgTE/g extract) and FRAC (369.54 � 1.70 mgTE/g extract) assays. In Phosphomolybdenum activity assay, PP-H and PP-E showed nearly similar potential, however, PP-H was the most active (13.54 � 0.24 mgEDTAE/g extract) in metal chelating activity assay. PP-W was the stronger inhibitor (4.03 � 0.05 mgGALAE/g extract) of the enzyme AChE, while PP-H was potent inhibitor of BChE (5.62 � 0.27 mg GALAE/g extract). Interestingly, PP-E was inactive against BChE. Against tyrosinase activity, PP-E was again the most active fraction with inhibitory value of 71.89 � 1.44 mg KAE/g extract, followed by the activity of PP-M and PP-W. Antidiabetic potential was almost equally distributed among PP-M, PP-H and PP-E. For mapping the chemodiversity of P. plebeium, PP-M was analyzed through UHPLC/MS, which led to the identification of more than 50 compounds. Flavonoids were the main components derived from isovitexin, kaempferol and luteolin however, gallic acid, protocatechuic acid, gingerols and lyoniresinol 9'-sulfate were among important bioactive phenols. These findings prompted to conclude that Polygonum plebeium can be a significant source to offer new ingredient for nutraceuticals and functional foods.

Serine protease, human neutrophil elastase (HNE), has been shown to be useful in medical science, however, its over production and malfunctioning may produce devastating effects and cause serious damage to the host. Unfortunately, the present approved drug, sivelestat, only alleviates the symptoms of the diseases caused by malfunction of HNE but not the disease progression. Therefore, there is crucial need to search potent and safer molecules as elastase inhibitors and to develop better anti-inflammatory drugs in future. In addition, Nature is the best architect that may provide a safer future drug candidate as HNE-production/activity inhibitor. Since phenolic natural products are already known as anti-inflammatory compounds, either by acting as antioxidants or by any other mechanism, thus, this review article summarizes the discovery and elastase inhibitory activity of 180 phenolics isolated from diverse natural sources during more than one decade, i.e. 2005-2017.