Characterization of natural monatin isomers, a high intensity sweetener from the plant Sclerochiton ilicifolius from South Africa

The objective was to establish the natural occurrence of the various isomers of monatin in extracts of Sclerochiton ilicifolius plant material harvested from different growing regions in South Africa. The natural occurrence of the 2S,4S isomer has been reported as well as the synthesis of the 2R,4R isomer. The 2R,4R is reported as the most intense sweetness however its natural occurrence has not been fully reported, as a result it was not possible to establish whether these isomers are indeed already present in the plant or come from racemisation during the processing of the plant. The presence of the monatin isomers 2S,4S; 2R,4R in aqueous extracts of S. ilicifolius root bark was demonstrated in each sample harvested at two different time points. The 2R,4R, 2S,4S, 2R,4S, and 2S,4R monatin isomers were absent in the aqueous extracts of S. ilicifolius stem and leaf samples, however was shown to be present in the root bark, and root core samples. This report confirms previous findings which suggested that the 2S,4S and 2R,4R monatin isomers occur naturally in S. ilicifolius.The CSIR (VPE6T)http://www.elsevier.com/locate/sajb2019-03-01hj2018Chemistr

Investigating volatile compounds in the vapour phase of (1) a hot water infusion of rhizomes, and of (2) rhizomes of Siphonochilus aethiopicus using head space solid phase microextraction and gas chromatography with time of flight mass spectrometry

Wild ginger, Siphonochilus aethiopicus, is a traditional remedy for the treatment of allergic asthma and other conditions. Preparations include hot infusions of rhizomes and steaming of the rhizomes and inhalation of the vapour. Volatile compounds in the vapour phase (representing the fraction that is inhaled) of both (1) a hot water infusion of fresh and air dried rhizomes and of (2) rhizomes were concentrated by head space solid phase microextraction (H/S-SPME) and analysed by gas chromatography with time of flight mass spectrometry (GC-TOFMS). Eucalyptol (1,8-cineole) was the major compound present in the vapour phase of a hot water infusion of fresh and dried rhizomes, and was also present as one of three major compounds in the vapour phase of fresh rhizomes. The drying of rhizomes caused a significant loss of eucalyptol and other compounds. Eucalyptol reportedly controls airway mucus hypersecretion and asthma. As such the presence of eucalyptol in the vapour phase of hot preparations may contribute to the anecdotal effectiveness of S. aethiopicus as a decongestant and traditional remedy for the treatment of allergic asthma.http://www.elsevier.com/locate/sajb2017-09-30hb2016Chemistr

Chemical examination of essential oil from stem, roots and fruit peels of Nigerian Citrus jambhiri

The chemical profiles of the stem, root and fruit peel essential oils of Citrus jambhiri were investigated. Pulverized plant samples (500 g) each was hydrodistilled using all-glass Clevenger-type apparatus to obtain the essential oils. Two-dimensional GC-TOFMS was used for compositional profiling of the extracted oils. Chemical profiling of the stem oil of C. jambhiri revealed the presence of 64 components (83.11 %), the root oil of C. jambhiri showed 55 components (74.21 %) and the fruit peel oil of C. jambhiri revealed 25 components (83.56 %). The major components of the stem oil of C. jambhiri is 3,4-dimethyl-1,5-cyclooctadiene(13.43 %); geijerene (14.38 %) and γ-terpinene (8.07 %) were observed as main constituents in C. jambhiri root oil whereas cis-linalool oxide (19.85 %), trans-linalool oxide (furanoid) (14.86 %), terpinen-4-ol (7.37 %) and limonene (4.64 %) were the major components of C. jambhiri fruit peel oil. Even though the samples were obtained from the same plant, the compositional profile of the essential oils from various plant parts differs.TET FUNDhttps://www.tandfonline.com/loi/teop202021-01-27hj2020Chemistr

Potential for identifying plant-based toxins on San hunter-gatherer arrowheads

The antiquity of the use of hunting poisons has received much attention in recent years. In this paper we present the results of a pilot study designed to detect the presence of organic compounds, typically of less than 1200 Da, from poisonous plants that may have been used as hunting poisons in the past. We used ultra-performance liquid chromatography connected to a Synapt G2 high-resolution MS-QTOF mass spectrometer (UPLC-QTOF-MS) to provisionally identify plant-based toxins present in (1) extracts of fresh plant material, (2) a blind control recipe consisting of three plant ingredients and (3) a Hei||om arrow poison of unknown ingredients. Although not all expected toxic compounds were identified, those that were identified compared favourably with those reported in the literature and confirmed through databases, specifically the Dictionary of Natural Products and ChemSpider. MS/MS fragmentation patterns and accurate mass were used for tentative identification of compounds because archaeological residues usually contain insufficient material for unambiguous identification using nuclear magnetic resonance. We highlight the potential of this method for accurately identifying plant-based toxins present on archaeological artefacts and unique (albeit non-toxic) chemical markers that may allow one to infer the presence of toxic plant ingredients in arrow poisons. Any chemical study of archaeological material should consider the unique environmental degradative factors and be sensitive to the oxidative by-products of toxic compounds

Identification of antidiabetic compounds from the aqueous extract of Sclerocarya birrea leaves

SUPPLEMENTARY MATERIALS : TABLE S1: 1H NMR and 13C NMR data of Myricetin (1) in methanol-d4 compared to those reported [35] in DMSO-d6; TABLE S2: 1H NMR and 13C NMR data of Myricetin-3-O-β-D-glucuronide (2) in methanol-d4 compared to those reported [36] in methanol-d4; TABLE S3: 1H NMR and 13C NMR data of Quercetin-3-O-β-D-glucuronide (3) in methanol-d4 compared to those reported by [37] in methanol-d4; FIGURE S4: Relative Glucose uptake activity of Marula fractions in C2C12 myocytes over a range of 0.01-100µg/ml. Activity is expressed relative % to the baseline glucose uptake (control) set at 0% and the positive control insulin (Ins) set at 100%. Active fraction (fraction 3) exhibited comparable potency to Insulin. p value < * p < 0.05, ** p < 0.01. *** p < 0.001; FIGURE S5: ESI negative-mode BPI chromatogram of compound 1 (Myricetin) isolated from Fraction 4; FIGURE S6: ESI negative-mode BPI chromatogram of compound 2 (Myricetin3-O-β-D-glucuronide) isolated from Fraction 3; FIGURE S7: ESI negative-mode BPI chromatogram of compound 3 (Quercetin-3-O-β-D-glucuronide) isolated from Fraction 3; FIGURE S8: MS fragmentation pattern of peak 1 overlaid with MSMS fragmentation pattern of peak 1; FIGURE S9: MS fragmentation pattern of peak 2 overlaid with MSMS fragmentation pattern of peak 2; FIGURE S10: MS fragmentation pattern of peak 3 overlaid with MSMS fragmentation pattern of peak 3; FIGURE S11: MS fragmentation pattern of peak 4 overlaid with MSMS fragmentation pattern of peak 4; FIGURE S12: MS fragmentation pattern of peak 5 overlaid with MSMS fragmentation pattern of peak 5; FIGURE S13: MS fragmentation pattern of peak 6 overlaid with MSMS fragmentation pattern of peak 6.DATA AVAILABILITY STATEMENT : All the data supporting the findings of this study are available within the article and/or its Supplementary Materials.Diabetes, a prevalent metabolic condition with a wide range of complications, is fast becoming a global health crisis. Herbal medicine and enhanced extracts are some of the therapeutic options used in the management of diabetes mellitus. The plant-derived molecules and their suitable structure modification have given many leads or drugs to the world such as metformin used as an antidiabetic drug. The stem extract of Sclerocarya birrea has been reported as a potent antidiabetic (glucose uptake) agent. However, the bioactive compounds have not been reported from S. birrea for treatment of diabetes. In this study, the spray-dried aqueous leaf extracts of S. birrea were investigated as an antidiabetic agent using a 2-deoxy-glucose (2DG) technique showing good stimulatory effect on glucose uptake in differentiated C2C12 myocytes with % 2DG uptake ranging from 110–180% that was comparable to the positive control insulin. Three compounds were isolated and identified using bioassay-guided fractionation of the spray-dried aqueous extract of S. birrea leaves: myricetin (1), myricetin-3-O- -D-glucuronide (2) and quercetin-3-O- -D-glucuronide (3). Their chemical structures were determined using NMR and mass spectrometric analyses, as well as a comparison of experimentally obtained data to those reported in the literature. The isolated compounds (1–3) were studied for their stimulatory actions on glucose uptake in differentiated C2C12 myocytes. The three compounds (1, 2 and 3) showed stimulatory effects on the uptake of 2DG in C2C12 myocytes with % 2DG uptake ranging from 43.9–109.1% that was better compared to the positive control insulin. Additionally, this is the first report of the flavonoid glycosides (myricetin-3-O- -D-glucuronide) for antidiabetic activity and they are the main bioactive compound in the extract responsible for the antidiabetic activity. This result suggests that the S. birrea leaves have the potential to be developed for treatment of diabetes.The Department of Science and Innovation, South Africa, University of KwaZulu-Natal, South Africa and Biomedical Research and Innovation Platform, South African Medical Research Council.https://www.mdpi.com/journal/moleculesam2023Chemistr

Phytochemical isolation of compounds from <i>Sceletium tortuosum</i> and activity testing against <i>Plasmodium falciparum</i>

Malaria is a major health care problem in tropical regions due to the increasing resistance of Plasmodium falciparum against widely available antimalarial drugs. Traditional societies relied on medicinal plants to treat parasitic infections. As a result, drugs like quinine and artemisinin were isolated from herbs and barks (Varughese et al. 2010). Sceletium tortuosum has been used as medicine for social and spiritual purposes by San hunter gatherers and Khoi pastoralists. Sceletium tortuosum is rich in alkaloids, one of the important classes of natural product producing treatment for parasitic infections (Kayser et al. 2002). Laboratory preparation of extracts of fresh S. tortuosum plant material was conducted mimicking traditional methods of preparation using organic solvents. Mesembrine was isolated from a methanol extract using conventional column chromatography. Sixteen extracts and mesembrine were evaluated for antiplasmodium activity using a plasmodium lactate dehydrogenase culture sensitivity assay with chloroquine as reference drug. Of the sixteen extracts, four showed activity against P. falciparum with IC50 ranging between 1.47 µg/mL and 7.32 µg/mL. Extracts prepared from stored material at -20 °C showed no antiplasmodium activity. The four originally active extracts were re-screened six months later, but the antimalarial activity could not be reproduced. To determine discrepancy in biological results, chemical profiling of the extracts was done using high performance liquid chromatography technique. Differences were observed in the profiles of the active extracts when compared to those of stored plant material. The instability of plant constituents observed could be a result of plant storage suggesting that the plant is best used when fresh

UPLC-MS analysis of cannabis sativa using tetrahydrocannabinol (THC), cannabidiol (CBD), and tetrahydrocannabinolic acid (THCA) as marker compounds: inhibition of breast cancer cell survival and progression

Cannabis sativa L. extracts were characterized by ultra performance liquid chromatography-mass spectrometry (UPLC-MS) using tetrahydrocannabinol (THC), cannabidiol (CBD), and tetrahydrocannabinolic acid (THCA) as marker compounds. The inhibitory effects of various extracts were determined on the survival and progression of highly metastatic breast cancer cells. A higher amount of CBD was found in the dichloromethane extract, and this was found to be effective in inhibiting breast cancer cell growth in vitro and in angiogenesis. Collectively, it may be concluded that CBD, THC, and THCA in the African variety of C. sativa can be used as marker compounds in UPLC-MS analysis. The ability of the plant to inhibit breast cancer cell survival and progression may affirm the traditional use of the drug as an anticancer agent.The National Research Foundation and DST-IKS Based Technology, South Africa.https://journals.sagepub.com/home/npxpm2020Chemistr

Potential of South African medicinal plants targeting the reduction of Aβ42 protein as a treatment of Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE : Twenty South African medicinal plant species were selected by conducting a literature review based on the relevant information of their reported traditional medicinal uses and scientific reports against Alzheimer's disease, dementia, anxiety, mental illness, depression, acetylcholinesterase inhibition, headache, epilepsy, convulsion, hysteria, and sedative effects. AIM OF STUDY : The goal of this study was to investigate the biological activity of the traditionally used medicinal plant extracts against Alzheimer's disease by in vitro screening of the extracts to determine their potential to decrease levels of Aβ42 protein. MATERIAL AND METHODS: Different plant parts (leaves, stem, bark, and stalks) of twenty selected plants were collected from the Manie van der Schijff Botanical Garden, University of Pretoria. Plant parts were dried, ground and then extracted using DCM:MeOH (1:1). We measured the levels of β-amyloid precursor protein proteolytic products in HeLa cells stably transfected with APP carrying the Swedish mutation using ELISA. RESULTS : Of 33 plant extract 10 (30.3%) were found active based on the potential to significantly reduce the production of Aβ42. Amongst them extracts of leaves of Xysmalobium undulatum (Apocynaceae), leaves of Cussonia paniculata (Araliaceae) and leaves of Schotia brachypetala (Fabaceae) potently decreased the production of Aβ42 by 77.3 ± 0.5%, 57.5 ± 1.3%, and 44.8 ± 0.1%, respectively. X. undulatum and S. brachypetala enhanced non-amyloidogenic processing of β-amyloid precursor protein, thereby decreasing Aβ42 level. We also showed that C. paniculata induced the decrease of Aβ42 level through inhibiting APP processing. In addition, we isolated two cardenolides, compound [A] and [B], from X. undulatum and found that they potently decreased the Aβ42 production. CONCLUSION : These data suggest that the extract of X. undulatum, C. paniculata, and S. brachypetala have potential to be developed for Alzheimer's disease treatment. These active extracts and compounds are considered for further studies which examine their efficacy towards the reduction of Aβ42 through inhibiting APP process.The University of Pretoria Post Graduate Research Support Bursay, South Africa and by the Bio-Synergy Research Project (NRF-2012M3A9C4048793) and the Bio & Medical Technology Development Program (NRF-2015M3A9A5030735) of the Ministry of Science, ICT, and Future Planning through the National Research Foundation, Republic of Korea.http://www.elsevier.com/locate/jethpharm2020-03-01hj2019Chemistr

A novel cardenolide glycoside isolated from Xysmalobium undulatum reduces levels of the Alzheimer’s disease-associated β-amyloid peptides aβ42 in vitro

Elevated levels of the amylo β-proteins (Aβ), particularly Aβ42, are associated with a high risk of Alzheimer’s disease (AD). The Aβ proteins are produced from cellular processing of the amyloid precursor proteins (APPs). To identify natural products that block the formation of Aβ-proteins from APPs, we previously screened a library of plant extracts and identified Xysmalobium undulaum (Apocynaceae) as a potential plant for further research. Here, we provide a report on the isolation and identification of the active principles from the plant species using a bioassay-guided fractionation. Fractions and resulting pure compounds from the purification process of the extract of X. undulatum were screened in vitro against APPs transfected HeLa cell lines. Three compounds, acetylated glycosydated crotoxogenin (1), xysmalogenin-3, β-D-glucopyranoside (2), and crotoxigenin 3-Oglucopyranoside (3), were subsequently isolated and their structures elucidated using NMR and mass spectrometry. Compound 1, a novel cardenolide, and 2 significantly decreased the Aβ42 levels in a dose-dependent manner while compound 3 was inactive. In silico investigations identified the AD’s β-secretase enzyme, BACE1, as a potential target for these compounds with the glycoside moiety being of significance in binding to the enzyme active site. Our study provides the first report of a novel cardenolide and the potential of cardenolides as chemical scaffolds for developing AD treatment drugs.The University of Pretoria Post Graduate Research Support Bursary, South Africa; the Bio-Synergy Research Project; the Bio & Medical Technology Development Program of the Ministry of Science, ICT, and Future Planning through the National Research Foundation, Korea.http://www.mdpi.com/journal/pharmaceuticalspm2022BiochemistryChemistryGeneticsMicrobiology and Plant Patholog

New alk(en)ylhydroxycyclohexanes with tyrosinase inhibition potential from Harpephyllum caffrum Bernh. gum exudate

SUPPLEMENTARY MATERIALS : FIGURE S1 to S36 containing 1D and 2D NMR spectra, FT-IR, ECD spectra and high-resolution mass spectra of compounds 1–4.This work presents the first report on the phytochemical investigation of Harpephyllum caffrum Bernh. gum exudate. A known cardanol, 3-heptadec-120-Z-enyl phenol (1) and three new alk(en)ylhydroxycyclohexanes, namely, (1R,3R)-1,3-dihydroxy-3-[heptadec-120(Z)-enyl]cyclohexane (2) (1S,2S,3S,4S,5R)-1,2,3,4,5-pentahydroxy-5-[octadec-130(Z)-enyl]cyclohexane (3) and (1R,2S,4R)- 1,2,4-trihydroxy-4-[heptadec-120(Z)-enyl]cyclohexane (4) were isolated from the gum. The structures of the compounds were determined by extensive 1D and 2D NMR spectroscopy and HR-ESI-MS data. The ethanolic extract of the gum was found to be the most potent tyrosinase inhibitor with IC50 of 11.32 g/mL while compounds 2 and 3, with IC50 values of 24.90 and 26.99 g/mL, respectively, were found to be potential anti-tyrosinase candidates from the gum. Gum exudate may be a potential source for non-destructive harvesting of selective pharmacologically active compounds from plants. The results also provide evidence that H. caffrum gum may find application in cosmetics as a potential anti-tyrosinase agent.The University of KwaZulu-Natal, University of Johannesburg and University of South Africa.https://www.mdpi.com/journal/moleculesam2023Chemistr