Natural Products Journal, The - Volume 10, Issue 2, 2020

Background: Rheum palmatum is a medically important plant in the Polygonaceae family. Its wild resources have been declining due to over-exploitation. It is important and urgent to investigate the genetic diversity for the conservation of R. palmatum. Methods: The Chloroplast DNA matK sequences were used to assess genetic diversity among and within populations in this species. The genetic diversity index was calculated by Dnasp, PERMUT and Arlequin 3.0 software, and a Neighbor-Joining (NJ)-tree was constructed by MEGA 5.0 software. Results: Nine haplotypes were obtained based on the matK sequence analysis in fifteen populations. We found a relatively high genetic diversity in species level (Hd = 0.7414), and the genetic diversity among populations (FST = 0.81582) was higher than that within populations (FSC = 0.69526) according to the AMOVA analysis. The genetic distance between populations ranged from 0 to 0.0044, which within populations ranged from 0 to 0.001761. There was a significant correlation between genetic distance and geographic distance (r = 0.601, P < 0.001) according to the SPSS analysis. Conclusion: The genetic diversity among populations was higher than that within populations due to geographic isolation and decline in gene flow among populations. This study is significant for further studies concerned with efficient collection and preservation of wild resource of R. palmatum.

Background: Strobilanthes crispus (L.) Bremek (Acanthaceae) leaves are used traditionally in Malaysia, Thailand, and Indonesia for anti-diabetic, anti-lytic, diuretic, and laxative purposes. Herb-drug interactions may potentiate or antagonize the absorption and metabolism of drugs which may result in potential toxicity. The aim of the present study was to investigate the effect of juice, hot aqueous, cold aqueous and methanol extracts of S. crispus leaves on phase I cytochrome 3A4 (CYP3A4) and Cytochrome 2E1 (CYP2E1) and phase II human liver enzyme UDP-Glucuronosyl Transferase (UGT). Methods: The herb-drug interactions of the leaf extracts and juice were determined by specific enzyme activity of CYP isoforms with specific probe substrate using spectrophotometry. CYP3A4 activity was measured for aminopyrine specific metabolite (formaldehyde) at 415 nm. CYP2E1 activity was determined using p-nitrophenol specific metabolite (p-nitrocatechol) at 535 nm. UGT activity was quantified through the consumption of p-nitrophenol by UGT at 405 nm. Results: All the S. crispus preparations showed significant inhibition of CYP3A4 activity. Only the methanolic extract showed a significant inhibition in CYP2E1. All the S. crispus extracts showed a significant effect on UGT activation at the higher concentration (1000 ng/ml). Only the cold aqueous extract and the juice showed UGT inhibition at lower concentration (1 ng/ml). Conclusion: S. crispus preparations showed in-vitro drug-herb interaction effects on human liver microsomes. Therefore, there is a possibility of drug-herb interaction could occur with S. crispus leaves through its effect on CYP3A4. Inhibition of the herb extracts on CYP2E1 could show anticarcinogenesis effects. The potency of drugs that metabolized via UGT pathway may be affected when co-administered with S. crispus leaf preparations.

Background: Protein misfolding can lead to aggregation and these protein aggregates are a fundamental cause of many neurodegenerative disorders such as Alzheimer's, Parkinson's, Huntington's, Prion disease and amyotrophic lateral sclerosis. In recent years, a wide variety of natural compounds have been investigated as protein aggregation inhibitors. Many investigations have reported the therapeutic effects of botanicals constituents and their derivatives in neurodegenerative diseases. Objective: In this study, we examined the effect of Perovskia abrotanoides Karel (P. abrotanoides) root extract on the 1,4-dithiothreitol (DTT)-induced aggregation of proteins. Methods: The anti-aggregation ability of P. abrotanoides root extract was studied using visible absorption spectroscopy (light scattering), fluorescence spectroscopy, and circular dichroism (CD) spectroscopy. Result: The protective effect of P. abrotanoides root extract was varied in the three different-sized proteins (insulin, α-lactalbumin, and ovotransferrin). Conclusion: The results showed that P. abrotanoides root extract was able to inhibit protein aggregations in a concentration-dependent manner due to the interaction of P. abrotanoides root extract with hydrophobic area of proteins.

Background: In recent years, more and more researches have shown that neurotransmitters can also be synthesized and released by peripheral non-neural cells. However, specificity and high sensitivity detection means were required for confirming ESCs autocrine glutamate and γ - aminobutyric acid (GABA). Glutamate and GABA are water-soluble and polar compounds which cannot be retained on a reversed phase C18 column, and their contents are often at a trace level. On the other hand, the biological matrix such as cell culture fluid contains a large number of amino acids, vitamins, carbohydrates, inorganic ions and other substances. Therefore, the main problem is the selection of the chromatographic column to avoid matrix interference. Objective: To establish a rapid and reliable method for the simultaneous determination of glutamate and GABA released from embryonic stem cells based on analytical chemistry. Methods: Glutamate and GABA released from mouse embryonic stem cells were determined on the basis of hydrophilic interaction chromatography coupled with electrospray ionization tandem Mass Spectrometry (HILIC- ESI- MS/MS), using isotope internal standards and substitution matrix method. Results: Undifferentiated embryonic stem cells autocrine glutamate and GABA and will reach releasing- reuptacking dynamic equilibriums at different time points. In contrast, neither glutamate nor GABA releasing could be detected from the MEFs, indicating the specificity release of the mESCs in the applied analytic method. Conclusion: A novel, simple, sensitive, selective and quantitative method was developed for determination of the glutamate and GABA from mouse embryonic stem cells.

Background: Antioxidant and antityrosinase activities of medicinal plants, together with their various health benefits have received attention in recent times. However, with wide ethnobotanical uses of Phyllanthus amarus, data on in-vitro skin depigmentation activity and cytotoxicity, as well as its impact on mediators of Reactive Oxygen Species (ROS) are still lacking. This present study is, therefore, designed to evaluate its tyrosinase inhibitory action, antioxidant potentials and cytotoxic activities. Methods: In this study, quantitative determination of polyphenols, flavanol, flavonol, flavonoids, Oxygen Reducing Antioxidant Capacity (ORAC), Trolox Equivalent Antioxidant Capacity (TEAC) were performed on the extracts of P amarus. Also, tyrosinase inhibitory efficacy of the hexane, methanol and aqueous extracts of Phyllanthus amarus were evaluated using ELISA-based methods. Cytotoxicity studies were done with mouse Sertoli (TM4) cells, using MTT assay and cell counts. Results: The hexane and aqueous extracts exhibited significant antityrosinase activity (p<0.05) (IC50= 116.08 and 129.25 μg/mL respectively) while its methanolic extract produces no statistically significant finding. Higher total polyphenol, flavonoids and flavonol were seen in the methanol fraction of the extract. Besides, higher radical cation scavenging (TEAC) activity was observed in the aqueous extract. These values were significant (p<0.0001), whereas ORAC results of the methanol extract show significantly (p<0.0001) higher oxygen reducing antioxidant potential than the aqueous extract. The aqueous extract showed the highest mitochondrial dehydrogenase activity at lower concentrations (0.01 to 10 μg/ml). Here, TM4 cell numbers were also significantly higher as compared to the untreated control. Sertoli cell viability was compromised after exposure to higher extract concentrations (100 to 1000 μg/ml). Conclusion: The hexane and aqueous extracts of Phyllanthus amarus possess good tyrosinase inhibitory action when compared to the reference kojic acid. Also, it demonstrated high antioxidant potentials by its ability to scavenge oxygen radicals, reduce ferric ion and inhibit ABTS radical. Lower extract concentrations stimulated Sertoli cell proliferation, which might be due to phytoestrogenic activities of Phyllanthus amarus conferred by its active, components, such as phyllanthin and hypophyllanthin.

Background: Microorganisms from understudied habitats have been shown to be an important source of novel bioactive compounds. Endophytes constitute an underexplored group of microorganisms, of which those from aquatic plants have been even less studied. Nelumbo nucifera (lotus) is an aquatic plant with medicinal properties. A screening program for endophytes from N. nucifera by our research group resulted in many microbial isolates, of which isolate L-003 was a promising candidate, exhibiting antimicrobial and antioxidant activities. Objectives: The major objectives were to characterize the endophyte L-003 for its antimicrobial and antioxidant properties, identify the constituent bioactive compounds by GC-MS and characterize their activities further using in silico software. Methods: L-003 was identified by PIBWin software. Antimicrobial activity of the aqueous and organic extracts of culture supernatant of L-003 was checked against a panel of bacteria and fungi. Since the ethyl acetate extract showed the best antimicrobial activity, it was further characterized by thin layer chromatography, an activity confirmed by bioautography and purified by column chromatography. Total antioxidant capacity was assayed by standard techniques. Partially purified metabolite fingerprints were identified by GC-MS analysis. Results: Based on morphological and biochemical analyses, isolate L-003 was identified as belonging to Streptococcus sp. All the organic solvent extracts showed antimicrobial activity. Ethyl acetate extract showed maximum antimicrobial activity against all selected targets and exhibited antioxidant activity too, though butanol and aqueous extracts showed higher antioxidant activity. Two compounds, Acetic acid,-hydroxy, methyl ester and Disulfide, dipropyl, were identified by GC-MS in the metabolite fingerprint. These compounds showed differences in observed and calculated retention indices and could, therefore, be novel. In silico activity, characterization confirmed the antimicrobial and antioxidant properties attributed to these compounds. Conclusion: This is the first study reporting metabolite fingerprinting, identification and characterization of bioactive compounds from an endophytic isolate of Nelumbo nucifera. We conclude that endophytes from aquatic plants could be prospective sources of bioactive compounds, in this case with antimicrobial and antioxidant activities.

Background: Carthamus caeruleus belongs to the Asteraceae family. The roots are traditionally used as healing agents. They help to heal burns and treat skin diseases. They are also used against joint inflammation and are very effective against diseases such as irritable bowel syndrome for cancer patients. Objectives: The purpose of this work was i) to study the chemical composition of i) the essential oil and hydrosol extract of Carthamus caeruleus, ii) to isolate the major component of both extracts and iii) to evaluate their antioxidant, antifungal and insecticidal activities. Methods: The essential oil and hydrosol extract obtained from the roots were studied by GC and GC/MS. The antioxidant activities were performed using two different methods i) Radical scavenging activity (DPPH) and ii) the Ferric-Reducing Antioxidant Power (FRAP), using BHT as a positive control. Whereas, the antifungal activity of the essential oil and Carlina oxide was investigated against plant fungi. The fumigation toxicity of C. caeruleus essential oil besides Carlina oxide was evaluated against adults of Bactrocera oleae better known as the olive fly. Results: The essential oil and hydrosol extract were mainly represented by acetylenic compounds such as carline oxide and 13-methoxy carline oxide. Carlina oxide was isolated and identified by 1H and 13C NMR spectroscopic means. The results showed that Carlina oxide presented interesting antioxidant and antifungal properties, while C. caeruleus root essential oil had better insecticidal activity. Furthermore, Carlina oxide has demonstrated promising in vivo antifungal activity to control infection of apples by Penicillium expansum. Conclusion: Carlina oxide can be used as a natural food preservative and alternative to chemical fungicides to protect stored apple against Penicillium expansum.

Background: Succinic acid can be used as a precursor of many industrially important chemicals and has an extensive application range to apply in different industrial areas, such as pharmaceutical and food industry. Objective: In this work, we isolated a strain of B. megaterium which produces succinic acid in optimized czapek medium for its production. Methods: A study of the production of this organic acid was realized in different media adding insoluble phosphate sources to czapek medium. Results: Two Bacillus strains ELI 24 and ELI30 that were isolated from soil in Mexico were fully characterized as Bacillus megaterium and B. thuringiensis. B. megaterium ELI 24 was proved to secrete succinic acid which was clearly identified by spectroscopic methods, such as 1H and 13C NMR, and X-ray analysis. Conclusion: This organic acid could improve the solubility of insoluble phosphate, which could help in the growth of plants.

Background: The genus Verbascum is well documented for its antioxidant potential but Verbascum sinaiticum is comparatively less studied plant. The current study was carried out to search for antioxidant nutraceuticals from this species. Objective: To explore the antioxidant potential of Verbascum sinaiticum and to identify its active constituents. Method: The methanolic extract of air-dried aerial part of the Verbascum sinaiticum was partitioned with hexane, chloroform and ethyl acetate. The water-soluble part of ethyl acetate afforded six phenylethanoid glycosides by repeated chromatography over Sephadex LH-20, silica gel and ODS columns. Antioxidant activity of solvent extracts and isolated constituents were evaluated by DPPH, ABTS and FRAP assays. Results: Six phenylethanoid glycosides was isolated and characterized as Verbascoside, Eukovoside, Martynoside, Jionoside D, Campneoside I and Campneoside II, from the most active fraction. Conclusion: Verbascum sinaiticum demonstrated prospective antioxidant activity. The watersoluble part of EtOAc (WSEAE) was found the most active extract whereas Verbascoside was identified as the most potent constituent. All isolated compounds exhibited significant antioxidant activity whereas their synergistic effect was found prominent in the parent fraction.

Background: In the flora of China and Vietnam, Luculia pinceana Hook of the family Rubiaceae is described as a medicinal plant. Prior chemical studies of L. pinceana in China isolated iridois, glycosides of cincholic acid, and kaempferol glycosides from the stem, however, have not been conducted with L. pinceana in Vietnam. Methods: The stem of L. pinceana was extracted with a mixture of 90%EtOH–H2O at room temperature and the extract was further fractionated by using liquid-liquid extraction and repeated column- chromatographic techniques. Spectroscopic data (IR, MS, 1D- and 2D-NMR) were used to determine structures of isolated compounds. Results: Thirteen compounds were isolated and structurally determined. Oleanolic acid (2), scopoletin (3), cleomiscosin A (4), (E)-mappianine E (5a), (Z)-mappianine E (5b), vanillic acid (6), 2-hydroxyacetophenone-4-O-β-D-glucopyranoside (7), sweroside (10), and 4-methoxyacetophenone- 2-O-β-D-glucopyranoside (11) were isolated for the first time from L. pinceana. Compounds 6, 10, 11, loganin (8), 7-ketologanin (9) were not active (IC50 > 300 μg/ml), whereas 7 showed a weak activity (IC50 268.35 μg/ml) in the DPPH (1,1-diphenylpicrazyl) radical scavenging assay. A mixture of 5a/5b was cytotoxic against the human cancer cell line HepG2 (IC50 100.57 μg/ml) in the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Conclusion: L. pinceana in Vietnam was investigated for the first time. We isolated compounds of varied biosynthetic origins including monoterpene indole, iridoid, coumarin, coumaro-lignoid, phytosterol, oleanane triterpenoid, phenolic acid, and acetophenone. Nine of the thirteen compounds are newly isolated from L. pinceana. The study determined weak scavenging activity of acetophenone (7) in the DPPH-scavenging assay and weak cytotoxicity of a mixture of two monoterpene indoles (5a and 5b) against HepG2 cell.

Background: Syzygium densiflorum Wall. ex Wight & Arn (Myrtaceae) has been traditionally used by the local tribes of the Nilgiris, Tamil Nadu, India, for the treatment of diabetes. Objective: This study aimed to isolate the major phytoconstituents from the S. densiflorum fruits and to perform computational studies for chemical reactivity and biological activity of the isolated compound. Materials and Methods: Two different compounds were isolated from ethanolic extract of S. densiflorum fruits and purified using HPLC. The structures of the compounds were elucidated on the basis of their 1H NMR, 13C NMR, 1H-1H COSY, HMBC, HRESIMS, and FT-IR data. Further, the chemical reactivity of the compounds was analyzed by density functional theory calculations and its therapeutic role in diabetic management was examined by comparing the structure of isolated compounds with previously reported bioactive compounds. Results: Of the two compounds ((6,6 & 1-kestopentaose (1) and 6-(hydroxymethyl)-3-[3,4,5- trihydroxy- 6-[(3,4,5-trihydroxyoxan-2-yl)oxymethyl]oxan-2-yl]oxyoxane-2,4,5-triol)(2)). β-glucosidase, β-galactosidase, α-glucosidase and β-amylase inhibition activity of the compounds were predicted by structure activity relationship. Conclusion: Structure-activity relationship analysis was performed to predict the therapeutic role of isolated compounds. These computational studies may be performed to minimize the efforts to determine the therapeutic role of natural compounds.

Background: The cortex of Mallotus japonicus (Euphorbiaceae) has traditionally been used to treat gastric ulcers, duodenal ulcers, and gastric hyperacidity in Japan. A large number of studies have recently focused on its effects on Inflammatory Bowel Disease (IBD). Objective: The aim of the present study was to examine the effects of M. japonicus (MJ) extracts on large intestinal diarrhea and inflammation using Inflammatory Bowel Disease (IBD) mouse models. Methods: The present study used 3% Dextran Sulfate Sodium (DSS)-treated colitis models. Red blood cell, platelet, and leukocyte counts in addition to hematocrit (Ht), hemoglobin (Hb), and colonic cytokine and chemokine levels were measured in DSS-treated C57BL/6J mice during the experimental period. Results: The Disease Activity Index (DAI) was lower in 3% DSS-treated mice orally administered MJ (200 and 500 mg/kg) than in mice administered 3% DSS only. Furthermore, MJ inhibited decreases in red blood cell and platelet counts as well as Hb and Ht levels in DSS-treated mice. Colon histology using direct fast scarlet staining revealed that MJ prevented mucosal membrane ulceration and eosinophil infiltration of the mucosal membrane induced by the DSS treatment. Increases in colonic Monocyte Chemoattractant Protein 1 (MCP)-1, interleukin (IL)-1β, and Tumor Necrosis Factor (TNF)-α levels in DSS-treated mice were reduced by orally administered MJ extracts. Conclusion: The present results suggest that M. japonicus cortex extracts are an effective treatment for IBD through the inhibition of increases in colonic IL-1β, TNF-α, and MCP-1 levels and eosinophil infiltration of the colon in DSS-treated mice.