Muntingia calabura: A comprehensive review

Medicinal plants are well-known sources of important therapeutic aid for alleviate human disorders. (Elaeocarpaceae) is the widely used in the ayurvedic system of the medicine as very sweet, musky, fig-like flavour. also known as Jamaica cherry, is a small and evergreen tree. The necessity of plant in human ailments is illustrious in old medicinal practices. The secondary metabolites are obtained from the different parts of plant alkaloids, flavonoids, tannin, phenolic compound etc. are traditional medicinal uses have been reported for the leaves (headaches, prostate problems, reduce gastric ulcers), bark (antiseptic), flowers (antiseptic, reduce swelling, antispasmodic), and fruits (respiratory problems, antidiarrheic). The present study gives an overview on plant and its pharmacological activities were documented.

Plant Alkaloids Inhibit Membrane Fusion Mediated by Calcium and Fragments of MERS-CoV and SARS-CoV/SARS-CoV-2 Fusion Peptides

To rationalize the antiviral actions of plant alkaloids, the ability of 20 compounds to inhibit calcium-mediated fusion of lipid vesicles composed of phosphatidylglycerol and cholesterol was investigated using the calcein release assay and dynamic light scattering. Piperine, tabersonine, hordenine, lupinine, quinine, and 3-isobutyl-1-methylxanthine demonstrated the most potent effects (inhibition index greater than 50%). The introduction of phosphatidylcholine into the phosphatidylglycerol/cholesterol mixture led to significant changes in quinine, hordenine, and 3-isobutyl-1-methylxanthine efficiency. Comparison of the fusion inhibitory ability of the tested alkaloids, and the results of the measurements of alkaloid-induced alterations in the physical properties of model membranes indicated a potent relationship between a decrease in the cooperativity of the phase transition of lipids and the ability of alkaloids to prevent calcium-mediated vesicle fusion. In order to use this knowledge to combat the novel coronavirus pandemic, the ability of the most effective compounds to suppress membrane fusion induced by fragments of MERS-CoV and SARS-CoV/SARS-CoV-2 fusion peptides was studied using the calcein release assay and confocal fluorescence microscopy. Piperine was shown to inhibit vesicle fusion mediated by both coronavirus peptides. Moreover, piperine was shown to significantly reduce the titer of SARS-CoV2 progeny in vitro in Vero cells when used in non-toxic concentrations.

Strictosidine Synthase Coding Gene Expression towards Quinine Biosynthesis and Accumulation: Inconsistency in Cultured Cells and Fresh Tissues of Cinchona ledgeriana

Strictosidine synthase, encoded by the gene STR, facilitates the regeneration of strictosidine, a critical intermediate for the synthesis of many plant alkaloids. The gene has, however, never been studied in Cinchona spp. The plants produce quinine alkaloid used for malaria medication, SARS-CoV-2 treatment and other industrial purposes. Cultured cells can produce the alkaloid but only at a much lower yield than the natural tree. This study describes STR expression and quinine content in various plant materials. Bioinformatic analyses were conducted on nine species of Rubiaceae to obtain reference sequences to design conservative primers for Cinchona ledgeriana STR (ClSTR). ClSTR expression was analyzed using qRT-PCR and quinine content was determined using HPLC. A complete coding sequence (CDS) of ClSTR was deposited in NCBI GenBank under the accession number MK422544.1. ClSTR was expressed in cultured cells, young and mature leaves, and stem bark. The elicited cells have higher expression than the control and they performed since the fourth week. However, the quinine content was greater in older cells. The gene expression in young leaves was superior, but quinine was most abundant in the stem bark. Every cell of C. ledgeriana, in culture or in the plant, expressed ClSTR and was capable of synthesizing the alkaloid quinine. The alkaloid from the leaves of the plant might be translocated and accumulated in the bark. No efflux of alkaloids from the confined cultured cells might contribute in triggering feedback inhibition in the biosynthetic pathway. This study revealed a critical obstacle in cell culture as a means of secondary metabolites production that needs further development of metabolic engineering. © 2021 Friends Science Publishers

Diversity in Chemical Structures and Biological Properties of Plant Alkaloids

Phytochemicals belonging to the group of alkaloids are signature specialized metabolites endowed with countless biological activities. Plants are armored with these naturally produced nitrogenous compounds to combat numerous challenging environmental stress conditions. Traditional and modern healthcare systems have harnessed the potential of these organic compounds for the treatment of many ailments. Various chemical entities (functional groups) attached to the central moiety are responsible for their diverse range of biological properties. The development of the characterization of these plant metabolites and the enzymes involved in their biosynthesis is of an utmost priority to deliver enhanced advantages in terms of biological properties and productivity. Further, the incorporation of whole/partial metabolic pathways in the heterologous system and/or the overexpression of biosynthetic steps in homologous systems have both become alternative and lucrative methods over chemical synthesis in recent times. Moreover, in-depth research on alkaloid biosynthetic pathways has revealed numerous chemical modifications that occur during alkaloidal conversions. These chemical reactions involve glycosylation, acylation, reduction, oxidation, and methylation steps, and they are usually responsible for conferring the biological activities possessed by alkaloids. In this review, we aim to discuss the alkaloidal group of plant specialized metabolites and their brief classification covering major categories. We also emphasize the diversity in the basic structures of plant alkaloids arising through enzymatically catalyzed structural modifications in certain plant species, as well as their emerging diverse biological activities. The role of alkaloids in plant defense and their mechanisms of action are also briefly discussed. Moreover, the commercial utilization of plant alkaloids in the marketplace displaying various applications has been enumerated.

Quantitative and Qualitative Assessment of Phytochemicals in Methanolic Extracts of Hurricane Weed (Phyllanthus amarus Schumach. &Thonn) Plant

The phytocomponents of the leaf and root extracts of Phyllanthus amarus (Euphorbiaceae) were studied. The constituents of the leaves and roots were identified and quantified by using GC-MS. Result from the phytochemical analyses showed the presence of saponins, tannins, phenolics, anthocyanins, and glycosides in both leaves and root of the plant. Alkaloids and triterpenoids were, however only absent in the root of P. amarus but present in the leaves of the plant. Flavonoids, coumarins and steroids were absent in the leaves but present in the root part. The mean concentration of the phytochemicals investigated in leaves are 0.73±0.01%, 1.85±0.03%, 1.12±0.01%, 1.80±0.01%, 1.59±0.50%, 0.13±0.10%, and 0.86±0.01%, for saponins, tannins, phenolics, anthocyanins, alkaloids, triterpenoids, and glycosides respectively, while the mean concentration of the phytochemicals investigated in roots are 0.91±0.01%, 1.53±0.03%, 0.70±0.01%, 2.97±0.10%, 2.47±0.03%, 0.62±0.01%, 0.90±0.01% and 2.02±0.10% for saponins, tannins, phenolics, steroids, flavonoids, anthocyanins, glycosides and coumarins respectively. Furthermore, the GC-MS analysis of methanol extracts of the leaves and root of P. amarus revealed the presence of three medicinally important bioactive compounds, which are: 9-Octadecenoic acid which has percentage of abundance of 92.23% and 82.46% in leaves and roots of the plant respectively, followed by n-Hexadecanoic acid and Tetradecanoic acid with their corresponding percentage of abundance of 7.7% and 17.54% for leaves and root. These analytical results suggest the plantto possess a significant role in phyto-medicine. The importance of this plant was discussed in line with the role they play in ethnomedicinal life of the people. Keywords: Phyllanthus amarus; Phytochemicals; GC-MS; methanolic extract; Phytocomponents

Machine learning discovery of missing links that mediate alternative branches to plant alkaloids

Engineering the microbial production of secondary metabolites is limited by the known reactions of correctly annotated enzymes in sequence databases. To expand the range of biosynthesis pathways, machine learning is herein demonstrated for the discovery of missing link enzymes, using benzylisoquinoline alkaloid production as a model application with potential to revolutionize the paradigm of sustainable biomanufacturing. Bacterial studies utilize a tetrahydropapaveroline pathway, whereas plants are reported to contain a more stable norcoclaurine pathway, which is exploited in yeast. However, committed aromatic precursors are currently produced by microbial enzymes that remain elusive in plants. Accordingly, the machine learning enzyme selection algorithm is first applied to clarify the early missing links in plant alkaloid pathways. Characterization of predicted sequences via metabolomics reveals distinct oxidases and carboxy-lyases, which complete a plant gene-only benzylisoquinoline alkaloid pathway from tyrosine. Synergistic application of aryl acetaldehyde producing enzymes results in enhanced production through hybrid norcoclaurine and tetrahydropapaveroline pathways. Transplantation of features into homologous enzyme templates leads to the highest levels of bacterial norcoclaurine and N-methylcoclaurine. Mechanism-directed isotope tracing patterns confirm alternative flux branches from aromatic precursors to alkaloids. This machine learning-driven workflow can be adapted to numerous pathways.