Prenylated flavonoids from the root bark of Berchemia discolor, a Tanzanian medicinal plant

Geranylated or prenylated flavonoids from Cajanus volubilis

Five new flavonoid derivatives, cajavolubones A-E (1-5), along with six known analogues (6-11) were isolated from Cajanus volubilis, and their structures were elucidated by spectroscopic analysis and quantum chemical calculations. Cajavolubones A and B (1 and 2) were identified as two geranylated chalcones. Cajavolubone C (3) was a prenylated flavone, while cajavolubones D and E (4 and 5) were two prenylated isoflavanones. Compounds 3, 8, 9 and 11 displayed cytotoxicity against HCT-116 cancer cell line.

Isoprenylated Flavonoids as Cav3.1 Low Voltage-Gated Ca2+ Channel Inhibitors from Salvia digitaloides

Saldigones A-C (1, 3, 4), three new isoprenylated flavonoids with diverse flavanone, pterocarpan, and isoflavanone architectures, were characterized from the roots of Salvia digitaloides, together with a known isoprenylated flavanone (2). Notably, it's the first report of isoprenylated flavonoids from Salvia species. The structures of these isolates were elucidated by extensive spectroscopic analysis. All of the compounds were evaluated for their activities on Cav3.1 low voltage-gated Ca2+ channel (LVGCC), of which 2 strongly and dose-dependently inhibited Cav3.1 peak current.

A comprehensive review: Biological activity, modification and synthetic methodologies of prenylated flavonoids

Prenylated flavonoids, a unique class of flavonoids which combine a flavonoid skeleton and a lipophilic prenyl side-chain, possess great potential biological activities including cytotoxicity, anti-inflammation, anti-Alzheimer, anti-microbial, anti-oxidant, anti-diabetes, estrogenic, vasorelaxant and enzyme inhibition. Recently, prenylated flavonoids have become an indispensable anchor for the development of new therapeutic agents, and have received increasing from medicinal chemists. The prenylated flavonoids have been outstanding developed through isolation, semi or fully synthesis in a very short period of time, which proves the great value in medicinal chemistry researches. In this review, research progress of prenylated flavonoids including natural prenylated flavonoids, structural modification, synthetic methodologies and pharmacological activities was summarized comprehensively. Furthermore, the structure-activity relationships (SARs) of prenylated flavonoids were summarized which provided a basis for the selective design and optimization of multifunctional prenylated flavonoid derivatives for the treatment of multi-factorial diseases in clinic.

Vhavenda Herbal Remedies as Sources of Antihypertensive Drugs: Ethnobotanical and Ethnopharmacological Studies

Hypertension is a dominant risk factor for the development of cardiovascular, kidney, and eye diseases. In Africa, it increasingly leads to hospitalisation and a strain on the public health system. However, rather than modern medicine, African traditional healers are the first choice for most South Africans. Therefore, this study is aimed at gathering information on herbal remedies traditionally used for the treatment of high blood pressure in Vhavenda, South Africa, and comparing this information with reports in the literature regarding plants used to manage high blood pressure. An ethnobotanical survey was carried out in Vhembe district and its environs with 53 herbalists and indigenous people aged between 36 and 66 years from January to October 2019 using a semistructured questionnaire. The plants were collected with each respondent; they were authenticated and kept in herbarium. A total of 51 different plants were mentioned as being most commonly used for hypertension treatment. Of these, 44 plants were identified, with those from the Fabaceae family followed by plants from the Celastraceae family being commonly mentioned. Of these, the Elaeodendron transvaalense, Tabernaemontana elegans, Elephantorrhiza elephantina, and Aloe vossii were commonly cited species. According to the literature data, most of the identified plants are yet to be scientifically investigated for the treatment of hypertension, whereas only preliminary investigations have been carried out on other plants, suggesting that these preliminary investigations may have highlight promising antihypertensive activities in vitro that are indicative of their potential as antihypertensive drugs. Therefore, there is a need to scientifically investigate the antihypertensive potentials of these plants as a potential source of antihypertensive treatment and compounds.

Synthesis of Isoflavones by Tandem Demethylation and Ring-Opening/Cyclization of Methoxybenzoylbenzofurans

The unexpected conversion of benzoylbenzofurans into isoflavones through an intramolecular cascade that involves deprotection and ring-opening/cyclization is described. This was discovered in an investigation of the possible transformation of benzoylbenzofurans into coumaronochromones. This route affords isoflavones in two major steps from acetophenones and benzoquinones. The transformation was validated by synthesizing differently substituted isoflavone derivatives and further applied to a concise synthesis of a potential anticancer lead compound, glaziovianin A (1).

Berchemiosides A-C, 2-Acetoxy-ω-phenylpentaene Fatty Acid Triglycosides from the Unripe Fruits of Berchemia berchemiifolia

Three compounds in a new class of 2-acetoxy-ω-phenylpentaene fatty acid triglycosides, berchemiosides A-C (1-3), and a biosynthetically related phenolic glycoside (4) were isolated from the unripe fruits of Berchemia berchemiifolia, along with three flavonoid 5-O-diglycosides (5-7) and three known flavonoids (8-10). Their chemical structures including absolute configurations were determined by spectroscopic analysis in combination with chemical derivatization. The pentaene group of 1 was found to have (6E,8E,10Z,12Z,14E)-geometry, whereas those of 2 and 3 exhibited all-E geometries. The isolated compounds were examined for their cytotoxicity and xanthine oxidase (XO) inhibitory activity; only compound 7 showed weak XO inhibitory activity.

[Synergistic Antitumor Effect of Amorphigenin Combined with Cisplatin in Human Lung Adenocarcinoma A549/DDP Cells]

背景与目的

Amorphigenin是从紫穗槐属植物的种子中分离提取的鱼藤酮类化合物，研究发现amorphigenin对多种肿瘤细胞具有增殖抑制作用。本研究拟探讨amorphigenin对人肺腺癌耐顺铂细胞株A549/DDP的抗肿瘤作用及其可能的分子机制。

方法

采用CCK-8法测定A549/DDP细胞的增殖；克隆形成实验测定A549/DDP细胞的克隆形成；流式细胞术检测细胞的凋亡率；Western blot技术检测caspase-3、PARP和LRP蛋白的表达。

结果

Amorphigenin可抑制A549/DDP细胞的增殖48 h[半数抑制浓度(half maximal inhibitory concentration, IC₅₀)]为(2.19±0.92)μmol/L、抑制克隆形成及诱导细胞凋亡。此外，Amorphigenin与顺铂联合可协同地抑制A549/DDP细胞生长和促进凋亡；降低耐药蛋白LRP蛋白的表达。

结论

Amorphigenin可抑制A549/DDP细胞增殖和促进细胞凋亡；amorphigenin可能是通过抑制耐药蛋白LRP蛋白表达，进而与顺铂对A549/DDP细胞产生协同抑制作用。

Cytotoxicities of two new isoflavanes from the roots of Dalbergia velutina

Two new isoflavanes, dalvelutinanes A (1) and B (2), along with three known isoflavanes (3-5) were isolated from the roots of Dalbergia velutina. Their chemical structures, including their absolute configurations, were determined by spectroscopic analysis (1D and 2D NMR, HRESIMS, and CD). All isolated compounds were evaluated for their in vitro cytotoxicities against five human cancer cell lines (KB, HeLa-S3, MCF-7, HepG-2, and HT-29). Compound 5 showed significant cytotoxicity against all of the tested cancer cell lines, with IC₅₀ values in the range 3.47-9.76 µM. In addition, compound 3 showed significant cytotoxicity against the KB and HeLa-S3 cells, with IC₅₀ values of 8.29 and 9.54 µM, respectively, and compound 2 showed significant cytotoxicity against the MCF-7 cell line, with an IC₅₀ value of 4.69 µM.

Pterocarpans from the Root Bark of Aeschynomene Fascicularis

A new pterocarpan, aeschynocarpin (1), and the known pterocarpan 2-methoxymedicarpin (2) were isolated for the first time from Aeschynomene fascicularis (Fabaceae) and their structures elucidated by means of spectroscopic {UV/Vis, IR, and NMR (1H, 13C, COSY, HMQC, and HMBC)} and mass spectrometric (EI-MS and HRCIMS) techniques. Both compounds were tested in vitro for their cytotoxic and antiproliferative activities against a panel of cancer cell lines. This is the first report on the presence of pterocarpans in the genus Aeschynomene.

Traditional use of medicinal plants in south-central Zimbabwe: review and perspectives

BACKGROUND

Traditional medicine has remained as the most affordable and easily accessible source of treatment in the primary healthcare system of resource poor communities in Zimbabwe. The local people have a long history of traditional plant usage for medicinal purposes. Despite the increasing acceptance of traditional medicine in Zimbabwe, this rich indigenous knowledge is not adequately documented. Documentation of plants used as traditional medicines is needed so that the knowledge can be preserved and the utilized plants conserved and used sustainably. The primary objective of this paper is to summarize information on traditional uses of medicinal plants in south-central Zimbabwe, identifying research gaps and suggesting perspectives for future research.

METHODS

This study is based on a review of the literature published in scientific journals, books, reports from national, regional and international organizations, theses, conference papers and other grey materials.

RESULTS

A total of 93 medicinal plant species representing 41 families and 77 genera are used in south-central Zimbabwe. These plant species are used to treat 18 diseases and disorder categories, with the highest number of species used for gastro-intestinal disorders, followed by sexually transmitted infections, cold, cough and sore throat and gynaecological problems. Shrubs and trees (38% each) were the primary sources of medicinal plants, followed by herbs (21%) and climbers (3%). The therapeutic claims made on medicinal plants documented in south-central Zimbabwe are well supported by literature, with 82.8% of the plant species having similar applications in other regions of Zimbabwe as well as other parts of the world and 89.2% having documented biological and pharmacological properties.

CONCLUSION

This study illustrates the importance of traditional medicines in the treatment and management of human diseases and ailments in south-central Zimbabwe. Traditional medicines still play an important role in meeting basic health care of local communities in Zimbabwe.

Inhibitory properties of selected South African medicinal plants against Mycobacterium tuberculosis

ETHNOPHARMACOLOGICAL RELEVANCE

Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB) is the most commonly notified disease and the fifth largest cause of mortality. One in 10 cases is resistant to treatment in some areas. Several plants are used locally to treat TB-related disease.

AIMS OF THE STUDY

The aim was to screen selected South African medicinal plants used to treat TB and related symptoms by traditional healers for antimycobacterial activity.

MATERIALS AND METHODS

Ethnobotanical information on these plants was obtained. Crude acetone, methanol, hexane and ethanol extracts of 21 selected medicinal plants obtained in Venda, South Africa were screened for their ability to inhibit MTB H(37)Ra and a clinical strain resistant to first-line drugs and one second-line drug using tetrazolium microplate assay to determine the minimum inhibitory concentration (MIC). Results were analyzed using Microsoft Excel 2007 and One way ANOVA; p<0.05 was considered for statistical significance.

RESULTS

Few acetone extracts were active against MTB with MIC under 100 microg/mL. Four plants showed lower MIC values; Berchemia discolor Klotzsch Hemsl 12, 5 microg/mL on H(37)Ra and 10.5 microg/mL on the clinical isolate, Bridelia micrantha Hochst. Baill (25 microg/mL), Warbugia salutaris Bertol. F Chiov (25 microg/mL), and Terminalia sericea Burch ex D. F (25 microg/mL) on both H(37)Ra and clinical isolate. However, the roots of Ximenia caffra Sond. Var. caffra, barks of Sclerocarya birrea (A Rich) Hochst, Asclepias fruticosa L, tubers of Allium sativum L, leaves of Carica papaya L, Solanum panduriforme E. Mey C, and roots of Securidaca longepedunculata Fresen gave MIC greater than 100 microg/mL.

CONCLUSION

The acetone extracts of Berchemiadiscolor, Bridelia micrantha, Terminalia sericea and Warbugia salutaris could be important sources of mycobactericidal compounds against multidrug-resistant MTB.

Chemical constituents of the stem bark of Morus cathayana

Phytochemical investigation of the stem bark of Morus cathayana led to the isolation and identification of six new compounds, cathayanons F-J (1-5) and cathayanin A (6), and two known compounds, cathayanins B-C (7-8). Their structures were elucidated by spectroscopic methods. Compounds 1, 2, 3, 5, and 7 exhibited weak activities against five human cancer cell lines, with IC(50) values ranging from 4.7 to 9.8 microg/ml.

Cytotoxic, anti-proliferative and antimicrobial furanoditerpenoids from Stuhlmania moavi

The furanoditerpenoids voucapane, voucapane-6alpha,7alpha-diol, voucapane-18,19-diol and 18-hydroxyvoucapan-19-al were isolated from the cytotoxic stem and root bark extracts of Stuhlmaniamoavi Verdc. (Ceasalpiniaceae) and their structures established based on analysis of spectroscopic data. The compounds exhibited anti-proliferative, cytotoxic, antibacterial and antifungal activities, 18-hydroxyvoucapan-19-al showing the highest anti-proliferative and cytotoxic properties. Voucapane-18,19-diol was only mildly active but the activity was enhanced for its 18,19-di-(4-methyl)-benzenesulphonate. Some of these results thus corroborate the traditional medicinal uses of the crude extracts for the treatment of skin infections.

Bioactive natural products derived from the East African flora

This review describes bioactive natural products isolated from East African medicinal plants. It includes 211 bioactive compounds from 41 plant species, and cites 116 references.

Use of the in vivo hollow fiber assay in natural products anticancer drug discovery

The in vivo hollow fiber assay was developed at the National Cancer Institute (NCI) to help bridge the gap between in vitro cell-based assays and human tumor models propagated in immunodeficient mice. The goal was to develop an intermediate assay that could help predict which compounds found active in the 60-cell line panel would be active in a subsequent xenograft system. This was necessary due to the high cost of the traditional xenograft assay in terms of number of animals required, time for assay completion, and financial commitment necessary. To address this problem, investigators of the NCI Developmental Therapeutics Program designed a method of propagating human cancer cells in inert hollow fibers with pores small enough to retain the cancer cells but large enough to permit entry of potential chemotherapeutic drugs, including large proteins and other important substances. Fibers containing proliferating cancer cells are transplanted into the peritoneum or under the skin, the host mice are treated with a test agent, and the fibers are subsequently retrieved for analysis of viable cell mass. The assay has been successful in helping investigators from around the world, including our own research group, prioritize compounds active in vitro for further testing in the traditional xenograft system.

Natural products as aromatase inhibitors

With the clinical success of several synthetic aromatase inhibitors (AIs) in the treatment of postmenopausal estrogen receptor-positive breast cancer, researchers have also been investigating the potential of natural products as AIs. Natural products from terrestrial and marine organisms provide a chemically diverse array of compounds not always available through current synthetic chemistry techniques. Natural products that have been used traditionally for nutritional or medicinal purposes (e.g., botanical dietary supplements) may also afford AIs with reduced side effects. A thorough review of the literature regarding natural product extracts and secondary metabolites of plant, microbial, and marine origin that have been shown to exhibit aromatase inhibitory activity is presented herein.