Quassinoids with Inhibitory Activities against Plant Fungal Pathogens from Picrasma javanica

A bioactivity-guided study on the leaves of Picrasma javanica led to the isolation of 19 quassinoids, including 13 new compounds. The structures of the new compounds were elucidated by a combination of spectroscopic data analysis, X-ray crystallography studies, and electronic circular dichroism (ECD) data interpretation. Compounds 1-7 are rare examples of quassinoids with a keto carbonyl group at C-12. The biological activities of 11 of the more abundant isolates were evaluated against five phytopathogenic fungi in vitro, and several of them including 6 and 15 showed moderate inhibitory effects that were comparative to those of the positive control, carbendazim. In addition, the preliminary structure-activity relationships (SARs) of these quassinoids were also investigated.

Plantago major L. Extracts Reduce Blood Glucose in Streptozotocin-Induced Diabetic Mice

Plantago major L. (P. major L.) is a perennial plant belonging to the family Plantaginaceae. It has been used as a folk remedy for diabetes in Europe and Asia. However, the biologically active constituents responsible for the antidiabetic effects have not been reported. The objectives of this study aimed at determining the chemical components of Plantago major L. and evaluating the antidiabetic activity of the extracts using streptozotocin- (STZ-) induced diabetic mice. In this study, the Swiss mice were fed a high-fat diet to gain weight before STZ injections to induce diabetic conditions. The STZ-induced diabetic mice were orally treated with P. major L. extracts. The blood glucose test results from the treated diabetic mice and nontreated diabetic mice were compared. We found that a 15-day treatment with EP6 extract from P. major L. at a dose of 400 mg/kg could reduce the blood glucose level to the same level as a 15-day treatment with glucophage at a dose of 70 mg/kg. The major chemical components and structural characterization of EP6 extract were also reported. AST (aspartate transferase) and ALT (alanine aminotransferase) indicators of liver damage were measured in the treated and nontreated diabetic mice to give an overall view of the antidiabetic effect of P. major L. extracts.

Health Benefits of Quassin from Quassia amara: A Comprehensive Review of their Ethnopharmacological Importance, Pharmacology, Phytochemistry and Analytical Aspects

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Medicinal plants have been indispensable to human life as they are used in food, cosmetics, medicines, nutraceuticals, perfumery, beverages and many more sectors. The medicinal plant contains various important classes of phytochemicals and broadly they are categorized into either primary or secondary metabolite. A large number of modern medicines are mainly derived from plant and other natural sources. Medicinal properties of plants are mainly due to the presence of their secondary metabolite and good examples are salicylic acid, morphine, quinine, vincristin and vinblastine. In spite of the great discovery of allopathic medicine, plant pure phytoconstituents play an important role in the modern medicine. Various plant based medicine are available in the market and people are using it on the basis of the belief that it is safer compared to the allopathic medicine. Furthermore, based on these believes, people use most of the traditional medicines in their routine life for the treatment of numerous disorders and this is called self-medication. Quassia amara plant belongs to Simaroubaceae family which is one of the best examples of the self-medicated plant. Traditionally Quassia amara has antimalarial, stomachic, antianaemic, antibiotics, cytotoxic and antiamoebic activity. Its reproductive, insecticidal, larvicidal and vermifuge properties have been also reported in the literature. Quassinoids are the important phytoconstituents of this plant and are the main bitter principles of Quassia amara too. Quassin is a white crystalline substance and is widely used in Chinese herbal medicine for their bitter taste. The purpose of this review is to gain an understanding of the Quassin and Quassia amara and to present information and knowledge regarding this phytoconstituent. Medicinal uses, pharmacological importance and various bioanalytical methods of Quassin and Quassia amara have been presented in this review. The benefit of this review is to get better understanding and ideas of Quassin and Quassia amara research findings in various disciplines. Furthermore, there is a need to perform more scientific investigation to explore the other beneficial properties of Quassia amara and Quassin.

Quassinoids with Insecticidal Activity against Diaphorina citri Kuwayama and Neuroprotective Activities from Picrasma quassioides

Six new quassinoids, named kumulactone F (1), kumulactone G (2), kumulactone H (4), kumulactone I (5), kumulactone J (6), and kumulactone K (7), a pair of undescribed epimers α- and β-nigakihemiacetal G (3), 15 known quassinoids (8-22), and a mixture of the known compounds α- and β-neoquassin (23) were separated from the dried stems of the medical plants Picrasma quassioides. The chemical structures of all of the new compounds were established by spectroscopic data analyses (HR-ESI-MS, 1D and 2D NMR spectroscopy, and electronic circular dichroism (ECD)). Biologically, compounds 9 and 21 showed toxicity toward the Asian citrus psyllid Diaphorina citri Kuwayama with potent activity even equal to that of the positive control (Abamectin), compound 11 exhibited an excellent neuroprotective effect against SH-SY5Y cells which were pretreated by H₂O₂ with potent activity equal to that of the positive control (Trolox), and none of them showed cytotoxic activity toward the HeLa or A549 cell lines (IC₅₀ > 100 μM).

Antimalarial plants with potential male-factor antifertility properties

Malaria, caused mainly by Plasmodium falciparum among other Plasmodium species, is one of the main causes of death from parasitic diseases. Malaria is still a health problem mainly because of the cost of effective antimalarial drugs and the growing parasite resistance to conventional antimalarial drugs, making a great proportion of the people in malaria endemic countries dependent on plants for its treatment. Corollary, a large number of the rural populations consume antimalarial herbal preparations in large or excessive quantities despite the fact that it has been reported that some of them could cause male-factor infertility, a growing global health concern. Few studies have compiled information on the scientifically validated male-factor antifertility effects of these antimalarial plant remedies. The aim of this review therefore is to compile information on commonly used antimalarial plant remedies that have been experimentally validated as having male-factor antifertility effects. Thus, antimalarial plant remedies with experimentally confirmed male-factor antifertility potentials and compounds isolated from them are identified and discussed. The male-factor antifertility effects of these plants include reduction of sperm quality, regulation of reproductive hormone levels and induction of lipid peroxidation. Indiscriminate use of such antimalarial plants is discouraged when male contraception is not desired.

Quassinoids from Picrasma quassioides and Their Neuroprotective Effects

Quassinoids are a class of highly oxygenated degraded triterpenoids exclusively discovered from plants of the Simaroubaceae family. In this study, eight new (1-8) and 15 known quassinoids (9-23) were isolated from an extract of the stems of Picrasma quassioides. The structures were elucidated by spectroscopic analysis and electronic circular dichroism spectra combined with quantum chemical calculations. Compounds 4 and 5 represent the first examples of 18-nor-quassinoids from P. quassioides. All isolates were screened for their neuroprotective activities toward H₂O₂-induced cell damage in SH-SY5Y cells. Further study revealed that the potential protective activities of these compounds appeared to occur via the suppression of cell apoptosis and downregulation of caspase-3 activation.