A phenolic glycoside from Flacourtia indica induces heme mediated oxidative stress in Plasmodium falciparum and attenuates malaria pathogenesis in mice

Radiocarbon (14C) accelerator mass spectrometry as a convenient tool for differentiation of flavor chemicals of synthetic origin from biobased sources and their in-vivo toxicity assessment

Plants are known to be the natural factory for the production of flavor chemicals. Essential oils comprised of aldehyde as a functional group are potent in deciphering flavor effects in beverages and fresh and prepared food products. In the majority, these are manufactured through synthetic routes, resulting in high product carbon footprints or CO2 equivalents in total greenhouse gas emission. FDA has banned some of the synthetic flavor chemicals due to the health hazards associated with them. However, consumer's preference for natural is at stake due to the absence of quantitative traceability tools. The accelerator mass spectrometer (AMS) analysis revealed a distinction between natural and fossil-derived citral and its blends in Cymbopogon essential oils. The plant-derived citral contained a percent modern carbon (pMC) value in the range of 99-100 %. In contrast, the fossil fuel-derived citral showed zero pMC. Similarly, blends of Cymbopogon oils with 30-50 % (w/w) of fossil origin citral contained pMC equivalent to the proportions of modern carbon. These results showed the usefulness of AMS in quantifying the amount of 14C associated with flavor ingredients. Besides, acute oral toxicity data revealed Cymbopogon oils as the safe flavoring substance at the highest 2000 mg/kg body weight dose in Swiss albino mice.

Redox modulating small molecules having antimalarial efficacy

The search for effective antimalarial agents remains a critical priority because malaria is widely spread and drug-resistant strains are becoming more prevalent. In this review, a variety of small molecules capable of modulating redox processes were showcased for their potential as antimalarial agents. The compounds were designed to target the redox balance of Plasmodium parasites, which has a pivotal function in their ability to survive and multiply within the host organism. A thorough screening method was utilized to assess the effectiveness of these compounds against both drug-sensitive and drug-resistant strains of Plasmodium falciparum, the malaria-causing parasite. The results revealed that several of the tested compounds exhibited significant effectiveness against malaria, displaying IC50 values at a low micromolar range. Furthermore, these compounds displayed promising selectivity for the parasite, as they exhibited low cytotoxicity towards mammalian cells. Thorough mechanistic studies were undertaken to clarify how the active compounds exert their mode of action. The findings revealed that these compounds disrupted the parasites' redox balance, causing oxidative stress and interfering with essential cellular functions. Additionally, the compounds showed synergistic effects when combined with existing antimalarial drugs, suggesting their potential for combination therapies to combat drug resistance. Overall, this study highlights the potential of redox-modulating small molecules as effective antimalarial agents. The identified compounds demonstrate promising antimalarial activity, and their mechanism of action offers insights into targeting the redox balance of Plasmodium parasites. Further optimization and preclinical studies are warranted to determine their efficacy, safety, and potential for clinical development as novel antimalarial therapeutics.

A new phenolic glycoside from the leaves of Flacourtia flavescens Willd

Chemical study of the methanol extract from the leaves of Flacourtia flavescens led to the isolation of a new phenolic glucoside (1) along with fifteen known secondary metabolites namely shanzhiside methyl ester (2), aurantiamide acetate (3), caffeic acid methyl ester (4), caffeic acid (5), apigenin (6), luteolin (7), kaempferol (8), quercetin (9), gyrophoric acid (10), luteolin-7-O-β-D-glucopyranoside (11), luteolin-4'-O-β-D-glucopyranoside (12), kaempferol-7-O-α-L-rhamnopyranoside (13), kaempferol-3-O-β-D-glucopyranosyl-(1→6)-O-α-L-rhamnopyranoside (14), kaempferol-3,7-O-α-L-dirhamnopyranoside (15) and (2S,3S,4R,8E)-2-((2'R)-2'-hydroxy-octadecanoylamino)-lignocerane-1,3,4-triol-8-ene (16). Their structures were elucidated by 1D and 2D NMR analysis and mass spectrometry. The extracts and the isolated compounds were evaluated for their antibacterial activities. The EtOAc extract was highly active (MIC = 32 and 64 µg/mL) against E. coli and E. faecalis, respectively. Compounds 1, 2, 2b, 5, 8, 9, and 12 (MIC = 16-32 µg/mL) were moderately active against some tested bacteria.

An UPLC-Q-TOF/MS-Based Analysis of the Differential Composition of Dendrobium officinale in Different Regions

Dendrobium officinale (D. officinale) is a valuable traditional Chinese herbal medicine with high commercial value. In Chinese Pharmacopoeia (Ch.P., 2020 edition), the quality of D. officinale is mainly evaluated by its polysaccharide content. However, varying growth and production conditions, such as cultivation environment, origin, harvesting process, or processing methods, resulting in highly variable yields, quality, and composition. The aim of this study was to investigate whether the content of secondary metabolites in D. officinale from different origins is consistent with the polysaccharide content. The results showed that the polysaccharide content and pass rate were ranked as GX > AH > GZ > YN. Based on the nontargeted metabolomics approach, we searched for differential components in 22 different regions of D. officinale, including amides, bibenzyls, disaccharide, flavonoids, organic nitrogenous compounds, and phenolic glycosides. The overall expression was opposite to the polysaccharide, and the most expressed was YN, followed by GZ, AH, and GX. These results indicated that the current quality standard for evaluating the quality of D. officinale by polysaccharide content alone is imperfect, and small molecule compounds need to be included as quality markers.

Inhibition of heme detoxification pathway in malaria parasite by 3-hydroxy-11-keto-β-boswellic acid isolated from Boswellia serrata

Malaria eradication is still a major global health problem in developing countries, which has been of more concern ever since the malaria parasite has developed resistance against frontline antimalarial drugs. Historical evidence proves that the plants possess a major resource for the development of novel anti-malarial drugs. In the present study, the bioactivity guided fractionation of the oleogum-resin of Boswellia serrata Roxb. yielded the optimum activity in the ethyl acetate fraction with an IC₅₀ of 22 ± 3.9 μg/mL and 26.5 ± 4.5 μg/mL against chloroquine sensitive (NF54) and resistant (K1) strains of Plasmodium falciparum respectively. Further, upon fractionation, the ethyl acetate fraction yielded four major compounds, of which 3-Hydroxy-11-keto-β-boswellic acid (KBA) was found to be the most potent with IC₅₀ values 4.5 ± 0.60 µg/mL and 6.25 ± 1.02 μg/mL against sensitive and resistant strains respectively. KBA was found to inhibit heme detoxification pathways, one of the most common therapeutic targets, which probably lead to an increase in reactive oxygen species (ROS) and nitric oxide (NO) detrimental to P. falciparum. Further, the induced intracellular oxidative stress affected the macromolecules in terms of DNA damage, increased lipid peroxidation, protein carbonylation as well as loss of mitochondrial membrane potential. However, it did not exhibit any cytotoxic effect in VERO cells. Under in vivo conditions, KBA exhibited a significant reduction in parasitemia, retarding the development of anaemia, resulting in an enhancement of the mean survival time in Plasmodium yoelii nigeriensis (chloroquine-resistant) infected mice. Further, KBA did not exhibit any abnormality in serum biochemistry of animals that underwent acute oral toxicity studies at 2000 mg/kg body weight.

Phenyl glycosides from the leaves of Flacourtia indica (Burm. f.) Merr (Salicaceae)

Thirteen phenolic glycosides, together with fourteen various known compounds, were isolated from the methanolic extract of leaves of Flacourtia indica. Twelve of these were composed of gentisyl or salicyl alcohols, glycosylated on the phenol and acylated on the primary alcohol with various more or less oxidized forms of pyrocatechuic acid. A number of positions on the glucose or on the acid were further acylated by benzoic or cinnamic acid. In addition to these, a glucoside of a phenyl propanoid was also isolated. The gross structures were elucidated by spectroscopic means including 1D and 2D NMR experiments and HR-ESI-MS analyses. Several of these structures, for example, xylosmin, were previously described but it proved extremely difficult to conclude on their exact identity with the absence of clear data on absolute configuration in the literature.

Four new phenolics and antiparasitic secondary metabolites from Flacourtia rukam Zoll. & Mortizi

Phytochemical investigation of Flacourtia rukam Zoll. & Mortizi (F. rukam) leaves and bark led to the isolation and characterization of seventeen compounds of which four phenolics were not previously described; 2-[(benzoyloxy)methyl]-phenyl-O-β-xylosyl-(1→2)-β-glucopyranoside (1), 2-[(benzoyloxy)methyl]-4-hydroxyphenyl-O-β-xylosyl-(1→2)-β-D-glucopyranoside (2), 2-hydroxy-5-(2-hydroxyphenoxy)phenoxy-β-glucopyranoside (3) and biphenyl-1,1',2,2'-tetraol (5). Interestingly, the later compound is known as a synthetic but this is the first report for its isolation from nature. Chemical structures were established using extensive analysis of spectroscopic data (1 D and 2 D NMR and HRESIMS). Biphenyl-1,1,2,2'-tetrol (5) exhibited a good activity against Trypanosoma brucei trypomastigotes with IC₅₀= 6.66 ug/mL. Compounds 2, 5, 9, 10, 11 and 12 showed a good in-vitro anti-inflammatory activity using proteinase inhibitory assay. On the contrary, all tested compounds were inactive as antileishmanial or antimalarial.

Oxidative stress mediated cytotoxicity in leukemia cells induced by active phyto-constituents isolated from traditional herbal drugs of West Bengal

ETHNOPHARMACOLOGICAL RELEVANCE

In search of safe and effective therapeutic agents as alternative to synthetic chemotherapeutics for the treatment of leukemia, the herbal drugs (Leaf of Madhuca longifolia, leaf of Prosopis cineraria and bark of Flacourtia indica) with long traditional use in West Bengal have received our attention.

AIM OF THE STUDY

Present work was conducted to isolate and identify the active compounds of the selected herbal drugs using bio-assay guided fractionation and also to investigate their anticancer mechanism in leukemia cell lines.

MATERIALS AND METHODS

Bio-assay guided fractionation was used for the isolation of active constituents such as myricitrin, vitexin and vanillin from the aqueous extracts of M. longifolia, P. cineraria and F. indica, respectively using liquid partitioning and column chromatography and the compounds were characterized by HPLC, MS and NMR. Dose and time-dependent cytotoxicity of isolated compounds were studied against leukemia cells and their anticancer mechanism such as cell wall damage, nuclear damage, ROS and NO generation, SOD level, LDH release and lipid peroxidation were investigated.

RESULTS

Aqueous extract of M. longifolia, P. cineraria and F. indica exhibited maximum anti-proliferative activity against HL-60 (Acute myeloid leukemia, AML, 72.06%), K-562 (Chronic myeloid leukemia, CML, 42.14%) and Jurkat (Acute lymphoblastic leukemia, ALL, 51.71%) cells. Myricitrin, vitexin and vanillin exhibited dose-dependent (IC-50 values 164.4, 147 & 29.22 μg/ml) and time-dependent activity with maximum cytotoxicity at 48 h. All these three compounds caused apoptosis in leukemia cells by inducing free radicals such as ROS (1.33-2.65 Arbitrary units) and NO (11.17-18.53 μM), cell membrane damage and nuclear condensation which were evidenced by increased release of LDH (1326-1439 U/L), improved lipid peroxidation (10.19-14.41 nM/mg protein) and reduced SOD level (6.2-9.21 U/mg protein) in leukemia cells.

CONCLUSIONS

Based on anti-proliferative activity, the isolated phyto-compounds myrcitrin, vitexin and vanillin from M. longifolia, P. cineraria and F. indica could be developed as natural drugs for treating AML, CML and ALL leukemia types, respectively.

Chemical Constituents and Pharmacological Activities of Family Flacourtiaceae: A Class of Important Phytomedicine

Flacourtiaceae plants are widely used as folk medicines in traditional medicine systems for its chemical diversity and pharmacological activities. In many different areas, Flacourtiaceae plants are used as traditional medicines for the treatment of ulcers, malaria, rheumatism. The Flacourtiaceae plants contain a very plentiful chemical composition, and phytochemical studies show that the Flacourtiaceae plants contained terpenoids, aromatic glycosides, flavnoids, phenylpropanoids, alkaloids, fatty hydrocarbon, and other compounds. In pharmacological studies, various extract and isolated individual compounds exhibited antitumor, anti-oxidation, and anti-inflammatory activities. In this review, the literature data on the chemical constituents and pharmacological investigations of the Flacourtiaceae plants are summarized, to provide information about a more comprehensive chemical composition and detailed pharmacological activities of Flacourtiaceae plants, with a view of further development of clinical medication. However, research on quantitative analysis, toxicity, and drug safety in vitro and in vivo is still insufficient, and further research is required.

Antiplasmodial natural products: an update

Background

Malaria remains a significant public health challenge in regions of the world where it is endemic. An unprecedented decline in malaria incidences was recorded during the last decade due to the availability of effective control interventions, such as the deployment of artemisinin-based combination therapy and insecticide-treated nets. However, according to the World Health Organization, malaria is staging a comeback, in part due to the development of drug resistance. Therefore, there is an urgent need to discover new anti-malarial drugs. This article reviews the literature on natural products with antiplasmodial activity that was reported between 2010 and 2017.

Methods

Relevant literature was sourced by searching the major scientific databases, including Web of Science, ScienceDirect, Scopus, SciFinder, Pubmed, and Google Scholar, using appropriate keyword combinations.

Results and Discussion

A total of 1524 compounds from 397 relevant references, assayed against at least one strain of Plasmodium, were reported in the period under review. Out of these, 39% were described as new natural products, and 29% of the compounds had IC₅₀ ≤ 3.0 µM against at least one strain of Plasmodium. Several of these compounds have the potential to be developed into viable anti-malarial drugs. Also, some of these compounds could play a role in malaria eradication by targeting gametocytes. However, the research into natural products with potential for blocking the transmission of malaria is still in its infancy stage and needs to be vigorously pursued.

Targeting virulence factors as an antimicrobial approach: Pigment inhibitors

The fascinating and dangerous colored pathogens contain unique chemically pigmented molecules, which give varied and efficient assistance as virulence factors to the crucial reproduction and growth of microbes. Therefore, multiple novel strategies and inhibitors have been developed in recent years that target virulence factor pigments. However, despite the importance and significance of this topic, it has not yet been comprehensively reviewed. Moreover, research groups around the world have made successful progress against antibacterial infections by targeting pigment production, including our serial works on the discovery of CrtN inhibitors against staphyloxanthin production in Staphylococcus aureus. On the basis of the previous achievements and recent progress of our group in this field, this article will be the first comprehensive review of pigment inhibitors against colored pathogens, especially S. aureus infections, and this article includes design strategies, representative case studies, advantages, limitations, and perspectives to guide future research.

Human disorders associated with inflammation and the evolving role of natural products to overcome

Inflammation is a biological function which triggered after the mechanical tissue disruption or from the responses by the incidence of physical, chemical or biological negotiator in body. These responses are essential act provided by the immune system during infection and tissue injury to maintain normal tissue homeostasis. Inflammation is a quite complicated process at molecular level with the involvement of several proinflammatory expressions. Several health problems are associated with prolonged inflammation, which effects nearly all major to minor diseases. The molecular and epidemiological studies jagged that the inflammation is closely associated with several disorders with their specific targets. It would be great achievement for human health around the world to overcome on inflammation. Mostly used anti-inflammatory drugs are at high risk of side effects and also expensive. Hence, the plant-based formulations gained a wide acceptance by the public and medical experts to treat it. Due to extensive dispersal, chemical diversity and systematically established biological potentials of natural products have induced renewed awareness as a gifted source for medications. However, today's urgent need to search for cheaper, more potent and safe anti-inflammatory medications to overcome on current situation. The goal of this review to compile an update on inflammation, associated diseases, molecular targets, inflammatory mediators and role of natural products. The entire text concise the involvement of various cytokines in pathogenesis of various human disorders. This assignment discussed about 321 natural products with their promising anti-inflammatory potential discovered during January 2009 to December 2018 with 262 citations.