Flavonoids from Podocarpus macrophyllus and their cardioprotective activities

Antiviral and anti-inflammatory activities of chemical constituents from twigs of Mosla chinensis Maxim

Seven undescribed compounds, including three flavones (1-3), one phenylpropanoid (19), three monoaromatic hydrocarbons (27-29), were isolated from the twigs of Mosla chinensis Maxim together with twenty-eight known compounds. The structures were characterized by HRESIMS, 1D and 2D NMR, and ECD spectroscopic techniques. Compound 20 displayed the most significant activity against A/WSN/33/2009 (H1N1) virus (IC50 = 20.47 μM) compared to the positive control oseltamivir (IC50 = 6.85 µM). Further research on the anti-influenza mechanism showed that compound 20 could bind to H1N1 virus surface antigen HA1 and inhibit the early attachment stage of the virus. Furthermore, compounds 9, 22, 23, and 25 displayed moderate inhibitory effects on the NO expression in LPS inducing Raw 264.7 cells with IC50 values of 22.78, 20.47, 27.66, and 30.14 µM, respectively.

Natural products and their analogues acting against Mycobacterium tuberculosis: A recent update

Tuberculosis (TB) remains one of the deadliest infectious diseases caused by Mycobacterium tuberculosis (M.tb). It is responsible for significant causes of mortality and morbidity worldwide. M.tb possesses robust defense mechanisms against most antibiotic drugs and host responses due to their complex cell membranes with unique lipid molecules. Thus, the efficacy of existing front-line drugs is diminishing, and new and recurring cases of TB arising from multidrug-resistant M.tb are increasing. TB begs the scientific community to explore novel therapeutic avenues. A precise knowledge of the compounds with their mode of action could aid in developing new anti-TB agents that can kill latent and actively multiplying M.tb. This can help in the shortening of the anti-TB regimen and can improve the outcome of treatment strategies. Natural products have contributed several antibiotics for TB treatment. The sources of anti-TB drugs/inhibitors discussed in this work are target-based identification/cell-based and phenotypic screening from natural products. Some of the recently identified natural products derived leads have reached clinical stages of TB drug development, which include rifapentine, CPZEN-45, spectinamide-1599 and 1810. We believe these anti-TB agents could emerge as superior therapeutic compounds to treat TB over known Food and Drug Administration drugs.

A comprehensive review on the medicinal usage of Podocarpus species: Phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Plants of the Podocarpus species belong to the Podocarpaceae family and are largely distributed in the southern hemisphere. Beside the commercially and ecologically valuable, plants of the Podocarpus species are also used in traditional medicines in some countries for treating asthma, fever, venereal diseases, eye diseases, etc. AIM OF THE STUDY: In recent decades, the identities and pharmacological activities of phytochemicals extracted from Podocarpus plants have been widely studied. However, there have been no comprehensive and systematic reviews. This article aims to systematically review the latest research on the putative mechanisms underlying pharmacological actions of phytochemicals from the Podocarpus species, as well as to lay a foundation for promoting the development of plant resources from this genus, further drug research, and product development.

MATERIALS AND METHODS

A comprehensive search of PubMed, Google Scholar, Web of Science, Elsevier and CNKI databases was conducted using the keywords "Podocarpus", "traditional usage", "phytochemistry", "pharmacology", "nagilactone", etc. Related papers published among July 1964 to February 2023 were collected to summarize the research progress. All plant names were determined through the "The Plant List" (http://www.theplantlist.org/).

RESULTS

To date, 262 chemical constituents have been isolated and identified from 26 Podocarpus plants; among these, norditerpene bilactone is the main pharmacologically active component. Norditerpene bilactones are reported to have anti-cancer, anti-inflammatory, antioxidant, antibacterial, anti-tyrosinase, neuroprotective, anti-plasmodial, anti-mutagenic, and anti-atherosclerotic properties as well as other pharmacological activities, which support its traditional uses.

CONCLUSION

Extensive studies on phytochemistry and pharmacology of Podocarpus species lead to discovery of a series of hopeful leading compounds with unique chemical structure, especially the nor- and bis-norditerpenoid dilactones with four isoprene units. These compounds have been proved to possess various pharmacological activities. This review will provide a reference for further research and promote the idea of combining modern research with traditional medicinal applications of Podocarpus plants.

Phytochemical analysis and quality assessment of Podocarpus macrophyllus by UHPLC-DAD-ESI-MS and UHPLC-MS/MS MRM methods

The concern about the quality of medicinal herbs is becoming important due to the poor quality of commercial products like cosmetics, functional foods, and natural medicine produced from them. However, there is a lack of modern analytical methods to evaluate the constituents of P. macrophyllus until the moment. This paper reports an analytical method based on UHPLC-DAD and UHPLC-MS/MS MRM methods to evaluate the ethanolic extracts of P. macrophyllus leaves and twigs. 15 main constituents were identified using a UHPLC-DAD-ESI-MS/MS profiling. Subsequently, a reliable analytical method was established and successfully used to quantitate the constituent's content using four marker compounds in leaf and twig extracts of this plant. The result obtained from the current study demonstrated the secondary metabolites and the variety of their derivatives in this plant. The analytical method can help evaluate the quality of P. macrophyllus and develop high-value functional materials.

The complete chloroplast genome sequence of Podocarpus macrophyllus (Podocarpaceae) and phylogenetic analysis

The complete chloroplast genome sequence of Podocarpus macrophyllus was determined in this study. According to the results, the genome is 134,239 bp in length. The GC content of the whole chloroplast genome is 37.0%. The complete chloroplast genome of P. macrophyllus encodes a total of 120 genes, including 34 tRNA genes, 4 rRNA genes and 82 protein-coding genes. Like other conifers chloroplast genomes, P. macrophyllus has no inverted repeat sequences. To reveal the phylogenetic relationship of P. macrophyllus, we constructed phylogenetic trees using other species of Podocarpaceae, and the phylogenetic analysis showed that P. macrophyllus is evolutionarily closest to Podocarpus longifoliolatus.

The first synthesis of podocarflavone A and its analogs and evaluation of their antimycobacterial potential against Mycobacterium tuberculosis with the support of virtual screening

The first synthetic route developed for Podocarflavone A reported from Podocarpus macrophyllus and its analogs in 7 steps. Computational analysis for binding with the pantothenate kinase (3AVO) of Mycobacterium tuberculosis showed their docking score (ds) in the range of -8.9 to -9.3 Kcal/mol. MD simulations delineated the stability of the protein-ligand complexes in the TIP3P model. MMGBSA and MMPBSA values of 8d were -42.46 Kcal/mol and -14.58 Kcal/mol, respectively. Further in-vitro antitubercular screening of compounds 8a, 8d, and 8e against M. tuberculosis H37Ra using XRMA protocol exhibited promising antimycobacterial activity with IC₅₀ values 21.82 µg/mL, 15.55 µg/mL, and 16.56 µg/mL, respectively. Compounds 8a, 8d, and 8e showed antibacterial activity with IC₅₀ values 41.56 µg/mL, 24.72 µg/mL, and 72.45 µg/mL respectively against the Staphylococcus aureus. 8a and 8d showed inhibition with IC₅₀ values 39.6 µg/mL and 27.64 µg/mL, respectively, against Bacillus subtilis. The present study could help in the further development of lead molecules against tuberculosis.

Structural identification and UPLC-ESI-QTOF-MS2 analysis of flavonoids in the aquatic plant Landoltia punctata and their in vitro and in vivo antioxidant activities

Duckweeds have long been consumed as vegetables in several South Asian countries. In this study of the chemical constituents of duckweed Landoltia punctata, a new compound, apigenin 6-C-[β-D-apiofuranosyl-(1 → 2)]-β-D-glucopyranoside (1), and a previously LC-MS identified compound, quercetin 3-O-β-D-apiofuranoside (3), as well as three known compounds, luteolin 6-C-[β-D-apiofuranosyl-(1 → 2)]-β-D-glucopyranoside (2), apigenin 6-C-β-D-glucopyranoside (4), and luteolin 7-O-neohespirodise (5), were isolated and identified on the basis of MS and NMR spectroscopic analyses and chemical derivations. In total, 24 flavonoids were identified in L. punctata 0001 by UPLC-ESI-QTOF-MS². In DPPH and ABTS assays, 3 exhibited significant antioxidant activity with IC₅₀ values of 4.03 ± 1.31 µg/mL and 14.9 ± 2.28 µg/mL, respectively. In in vivo antioxidant activity assays, 1 significantly increased the survival rate of juglone-exposed Caenorhabditis elegans by 2 to 3-fold, and by 75% following thermal damage. Compounds 1-5 exhibited moderate scavenging capacities of intracellular reactive oxygen species in C. elegans exposed to H₂O₂.

Biflavonoids from Juniperus oblonga inhibit organic anion transporter 3

Organic anion transporters (OATs in humans, Oats in rodents) play an important role in the distribution and excretion of numerous endogenous metabolic products and exogenous organic anions, including a host of widely prescribed drugs. Their ligand recognition is also important for drug therapy and development. In this study, the n-butanol and dichloromethane soluble fractions of Juniperus oblonga were found to inhibit OAT3 in vitro and three biflavonoids were found to be responsible for this activity. One of these compounds, amentoflavone exhibited stronger inhibition than probenecid, a known strong inhibitor of OAT3. Biological characterization of amentoflavone in vivo also showed inhibition of Oat3. Preliminary observations of structure-activity relationships suggest that the biflavonoids are more potent inhibitors of this transporter than their corresponding monomer, and that methylation of even a single hydroxyl group results in a substantial decrease in activity. This greater potency of the biflavonoids may indicate the need for a more in-depth investigation of the distribution of biflavonoids in plants used as foodstuffs and herbal medicines, due to their potential for causing interactions with OAT3 substrate drugs.

Two New Anti-Proliferative C18 -Norditerpenes from the Roots of Podocarpus macrophyllus

Activity-guided fractionation strategy was used to investigate chemical constituents from the roots of Podocarpus macrophyllus. Successfully, two new norditerpenes, 2β-hydroxymakilactone A (1) and 3β-hydroxymakilactone A (2), along with ten known analogues (3 - 12) were isolated. The structures of 1 and 2 were elucidated by spectroscopic analysis including 1D-, 2D-NMR, and HR-ESI-MS data. The previously reported structure of 2,3-dihydro-2α-hydroxypodolide was revised as 2,3-dihydro-2β-hydroxypodolide (3) by spectroscopic analysis, and was further confirmed by X-ray crystallographic analysis. Cytotoxic activities of all isolated compounds against five human solid tumour cell lines (AGS, HeLa, MDA-MB-231, HepG-2, and PANC-1) were evaluated. All of them exhibited anti-proliferative activities (IC₅₀  = 0.3 - 27 μm), except for 10. Compounds 1, 4, 5, 6, and 8 exhibited potent inhibitory activities with IC₅₀  < 1 μm against HeLa and AGS cells.

Computational and Investigative Study of Flavonoids Active against Trypanosoma cruzi and Leishmania spp

Flavonoid compounds active against Trypanosoma cruzi and Leishmania species were submitted to several methodologies in silico: docking with the enzymes cruzain and trypanothione reductase (from T. cruzi), and N-myristoyltransferase, dihydroorotate dehydrogenase, and trypanothiona reductase (from Leishmania spp). Molecular maps of the complexes and the ligands were calculated. In order to compare and evaluate the antioxidant activity of the flavonoids with their antiprotozoal activity, quantum parameters were calculated. Considering the energies, interactions, and hydrophobic surfaces calculated, the flavonoids chrysin dimethyl ether against T. cruzi, and ladanein against Leishmania sp. presented the best results. The antioxidant activity did not show any correlation with anti-parasitic activity; only chrysin and its dimethyl ether showed favorable anti-parasitic results. This study hopes to contribute to existing research on these natural products against these tropical parasites.