Essential Oils of Five Syzygium Species Growing Wild in Vietnam: Chemical Compositions and Antimicrobial and Mosquito Larvicidal Potentials

The essential oils of five Vietnamese Syzygium species (Syzygium levinei, S. acuminatissimum, S. vestitum, S. cumini, and S. buxifolium) were first hydro-distilled and analyzed using GC-FID/MS (gas chromatography-flame ionization detection/mass spectrometry). Monoterpene hydrocarbons, sesquiterpene hydrocarbons, and oxygenated sesquiterpenoids were the main chemical classes in these oils. All these essential oils showed good-excellent antimicrobial activities against Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus, and the yeast Candida albicans. S. levinei leaf essential oil, rich in bicyclogermacrene (25.3%), (E)-β-elemene (12.2%), (E)-caryophyllene (8.2%), and β-selinene (7.4%), as well as S. acuminatissimum fruit essential oil containing (E)-caryophyllene (14.2%), α-pinene (12.1%), caryophyllene oxide (10.9%), β-selinene (10.8%), α-selinene (8.0%), and α-humulene (5.7%), established the same MIC value of 8 µg/mL against E. faecalis and B. cereus, which were much better than the positive control streptomycin (MIC 128-256 µg/mL). The studied essential oils showed the potential to defend against mosquitoes since they caused the 24 and 48 h LC50 values of less than 50 µg/mL against the growth of Culex quinquefasciatus and Aedes aegypti larvae. Especially, S. buxifolium leaf essential oil strongly inhibited Ae. aegypti larvae with 24 and 48 h LC50 values of 6.73 and 6.73 µg/mL, respectively, and 24 and 48 h LC90 values of 13.37 and 10.83 µg/mL, respectively. These findings imply that Vietnamese Syzygium essential oils might have potential for use as supplemental antibacterial agents or as "green" alternatives for the control of mosquitoes.

The genus Cratoxylum: traditional use, phytochemistry and pharmacology

OBJECTIVES

The genus Cratoxylum contained medicinal herbs, which are widely distributed in South-East Asia and China. Plants of this genus were consumed as a vegetable side dish, a spice, an ingredient in soup, or a substitute for tea, as well as they are traditionally appropriate for various diseases such as fever, cough, flu, diarrhoea, etc. The most aims of the current review are to highlight the ultimate information about the traditional use, phytochemistry and pharmacology of Cratoxylum medicinal plants.

KEY FINDINGS

The relevant literature data of Cratoxylum species have been gathered from Google Scholar, Sci-Finder, Web of Science, Science Direct and various journal websites. The most meaningful keyword 'Cratoxylum' was used in combination or alone in the search for references.

SUMMARY

More than 150 reports have been retrieved from the search, completely written in English. Most of them are phytochemical and pharmacological studies, which determined the isolations of 277 metabolites. Xanthone derivatives (205 compounds, 74%) are essential, followed by other chemical classes such as flavonoids, anthraquinones, triterpenoids, benzophenones, phytosterols and tocopherols. Cratoxylum constituents possessed complexed pharmacological activities, including antioxidant, antibacterial, anti-inflammatory, antidiabetic, antihypertensive, antimalarial, antiviral, antiamoebic, protein tyrosine phosphatase 1B inhibitory, neuroprotective, hepatoprotective and gastroprotective activities, especially in terms of anticancer.

Oxymatrine: A current overview of its health benefits

Oxymatrine (OMT), was identified as a quinolizidine alkaloid, which was one of the major matrine-type alkaloids extracted from Sophora medicinal plants. Growing studies revealed that OMT has a wide range of beneficial pharmacological values, consisting of anticancer, antidiabetic, antivirus, and antiinflammtion, as well as the protective activities to the brain, liver, heart, lung, vascular, gastrointestinal, bone, kidney, and skin organs. Various in vitro and in vivo models of pharmacological actions were recorded in regard to the usage of alkaloidal OMT. Mechanisms underlying anticancer activity of this compound may have been possibly involved anti-proliferation, invasion, migration, angiogenesis, epithelial-mesenchymal transition of cells, autophagy, especially apoptotic cell deaths. OMT could reduce hyperglycemia and hyperlipemia in a high-fat diet and streptozotocin-stimulated diabetic mice by improving insulin secretion and sensitivity. OMT suppressed gastric ulcer via gastric inflammatory and oxidative inhibitions, and pro-apoptotic actions. It turns out that OMT is relatively safe for cell and animal experiments. In this study, we offer a systematic review of natural occurrence, pharmacological potentials, possible mechanisms of action, pharmacokinetics, and bioavailability. Clinical research with OMT is needed to extensively elucidate its health potential benefits.

Wikstroemia: A Review on its Phytochemistry and Pharmacology

BACKGROUND

Wikstroemia (the family Thymelaeaceae) consists of medicinal plants which established great value in traditional medicines for many years. For instance, W. indica is always recommended for treatments of syphilis, arthritis, whooping cough, and cancer. No systematic review of bioactive compounds from this genus has been recorded to date.

OBJECTIVE

The objective of the current study is to review phytochemical investigations and pharmacological effects of Wikstroemia plant extracts and isolates.

METHODS

By searching on the internet, the relevant data about Wikstroemia medicinal plants were retrieved from internationally renowned scientific databases, such as Web of Science, Google Scholar, Sci-Finder, Pubmed, and so on.

RESULTS

More than 290 structurally diverse metabolites were separated and identified from this genus. They include terpenoids, lignans, flavonoids, coumarins, mono-phenols, diarylpentanoids, fatty acids, phytosterols, anthraquinones, and others. Pharmacological records indicated that Wikstroemia plant crude extracts and their isolated compounds bring out various beneficial effects, such as anticancer, antiinflammatory, anti-aging, anti-viral, antimicrobacterial, antimalarial, neuroprotective, and hepatoprotective activities Conclusion: Wikstroemia has been regarded as a worthy genus with numerous phytochemicals and various pharmacological potentials. Modern pharmacological studies have successfully provided evidence for traditional uses. Nonetheless, their action mechanisms need to be further investigated. Although various secondary metabolites were identified from Wikstroemia plants, the current pharmacological research mainly concentrated on terpenoids, lignans, flavonoids, and coumarins.

Genus Knema: An Extensive Review on Traditional Uses, Phytochemistry, and Pharmacology

BACKGROUND

Knema (the Myristicaceae family) is a large genus of small-medium trees found in Southeast Asia, Africa, and Australia. Historical records dealt with the uses of Knema species as medicinal plants against various diseases, especially cancer remedies, or their application as tonic agents in Asian communities Objective: The aim of this review is to provide the most current knowledge on the traditional uses, chemical profiles, as well as pharmacological values of Knema plants.

METHODS

Through electronic search, the literature materials on Knema plants were acquired from scholarly journals, books, and internationally recognized scientific databases, such as PubMed, ScienceDirect, Sci-Finder, Web of Science, and Google Scholar. All full-text articles and abstracts on Knema were screened. Genus Knema, traditional use, phytochemistry, and pharmacology were the first selective keywords to search for references.

RESULTS

Since the 1970s, more than 185 metabolites have been isolated from Knema plants and structurally elucidated. Among them, phenolic lipids, flavonoids, and lignans are the principal metabolites. Crude extracts, fractions, and isolated compounds of Knema species possess a wide variety of pharmacological properties, such as antioxidative, antidiabetic, antimicrobial, anti-inflammatory, antimalarial, neuroprotective, and hepatoprotective activities, but cytotoxicity is the most striking feature. Phenolic lipids containing long alkyl side chains and polar hydroxyl or acyl groups are found as the most active molecules in cytotoxic assays.

CONCLUSION

Further studies on phytochemistry and pharmacological activities, toxicological assessments, pharmacological mechanisms, and pharmacokinetics are urgently needed.

Wedelolactone: A molecule of interests

BACKGROUND

The search for bioactive molecules from medicinal plants of the family Asteraceae has been one of the targets in various phytochemical and pharmacological investigations for many years. According to these studies, wedelolactone, a coumestan of the secondary metabolite type, is a key compound found in several Eclipta and Wedelia herbal plants. To date, numerous experimental studies with intention of highlighting its role in drug development programs were carried out, but an extensive review is not sufficient.

OBJECTIVE

The current review aims to fill the gaps in extensive knowledge about phytochemistry, synthesis, pharmacology, and pharmacokinetics of coumestan wedelolactone.

MATERIALS AND METHODS

The databases Google Scholar, Scopus, PubMed, Web of Science, Science Direct, Medline, and CNKI were used to compile the list of references. In order to find references, "wedelolactone" was considered separately or in combination with "phytochemistry", "synthesis", "pharmacology", and "pharmacokinetics." Since the 1950s, >100 publications have been collected and reviewed.

RESULTS

Wedelolactone is likely to be a characteristic metabolite of two genera Eclipta and Wedelia, the family Asteraceae, while it could be synthetically derived from mono-phenol derivatives, through Sonogashira and cross-coupling reactions. Numerous biomedical investigations on wedelolactone revealed that its pharmacological values included anticancer, antiinflammatory, antidiabetic, antiobesity, antimyotoxicity, antibacterial, antioxidant, antivirus, anti-aging, cardiovascular, serine protease inhibition, especially its protective health benefits to living organs such as liver, kidney, lung, neuron, eye, bone, and tooth. The combination of wedelolactone and potential agents is a preferential approach to improve its biomedical values. Pharmacokinetic study exhibited that wedelolactone was metabolized in rat plasma due to hydrolysis, open-ring lactone, methylation, demethylation, and glucuronidation.

CONCLUSIONS

Wedelolactone is a promising agent with the great pharmacological values. Molecular mechanisms of the actions of this compound at both in vitro and in vivo levels are now available. However, reports highlighting biosynthesis and structure-activity relationship are still not adequate. Moreover, chemo-preventive records utilizing nano-technological approaches to improve its bioavailability are needed since the solubility in the living body environment is still limited.

Botanical Description, Traditional Uses, Phytochemistry, and Pharmacology of the Genus Artabotrys : A Review

Artabotrys is a genus of small trees in the family Annonaceae. This genus contained over 100 perennial medicinal plants available in the old world tropics. Artabotrys plants have a lengthy history of use in medicine for malaria, diarrhea, backache, and scrofula treatments, as well as some of which were used as tea-like beverages. About 90 reports were reviewed from inception to now. With 234 isolated compounds, Artabotrys metabolites can be classified as alkaloids, terpenoids, sterols, flavonoids, polyoxygenated cyclohexenes, fatty acids, acetogenins, etc. Significantly, alkaloidal aporphines were separated and identified as the main isolates. Artabotrys plants are also rich in essential oils, especially, A. hexapetalus exerted a great role in perfumery industry. Artabotrys constituents possessed various pharmacological values, such as antioxidative, antidiabetic, hepatoprotective, and mosquito repellency, but cytotoxic and antimicrobial activities are the most striking features.

The Medicinal Plant Agrimonia pilosa Ledeb.: Botanical Description, Traditional Use, Phytochemistry and Pharmacology

BACKGROUND

Hairy agrimony (Agrimonia pilosa Ledeb.) is a traditional medicinal plant widely used in Eastern Europe and Eastern Asia regions. The plant is harvested as it came into flower and could be dried for later usage. Hairy agrimony has been traditionally introduced to treat sore throat, abdominal pain, headache, mucoid dysentery, bloody and white discharge, parasites, and eczema.

OBJECTIVE

Since the 1950s, various experimental reports relating to phytochemical and pharmacological aspects have been observed, but an overview is now not available. The current paper emphasizes on in-depth information about botanical description, traditional use, phytochemistry, and pharmacology.

METHODS

The collection of previous research is basically depended on the reliable resources Sci-Finder, Google Scholar, ScienceDirect, reputation publishers, and thesis books.

RESULTS

A. pilosa was found to contain a variety of chemical classes. To date, more than 160 secondary metabolites were separated, and the derivatives type flavonoids, phloroglucinols, tannins, isocoumarins, and triterpenoids are the main components. A. pilosa crude extracts and their isolates set a broad panel of pharmacological values, including anti-cancer, anti-microbial, anti-virus, anti-oxidant, anti-inflammation, anti-diabetes, anti-osteosarcoma, anti-aging, anti-nociception, anti-adipogenesis, anti-leishmaniasis, estrogenic-like activity, neuroprotective and hepatoprotective activities, and vascular relaxation.

CONCLUSION

In vitro and in vivo results also successfully explained the pharmacological mechanisms of A. pilosa constituents. More bioassay-guided phytochemical and clinical studies are necessary.

A comprehensive review on phytochemistry and pharmacology of genus Kopsia: monoterpene alkaloids - major secondary metabolites

Kopsia belongs to the family Apocynaceae, which was originally classified as a genus in 1823. Kopsia consists of medicinal plants that can be traditionally used to treat rheumatoid arthritis, pharyngitis, tonsillitis, and dropsy. More than one hundred and twenty-five publications have been documented relating to the phytochemical and pharmacological results, but a systematic review is not available. The goal of this study is to compile almost all of the secondary metabolites from the plants of genus Kopsia, as well as the coverage of their pharmacological research. The document findings were conducted via reliable sources, including Web of Science, Sci-Finder, Science Direct, PubMed, Google Scholar, and publishers, while four words “Kopsia”, “monoterpene alkaloids”, “Phytochemistry” and “Pharmacology” are key factors to search for references. Most Kopsia secondary metabolites were collected. A total of four hundred and seventy-two, including four hundred and sixty-six monoterpene alkaloids, five triterpenoids, and one sterol, were summarized, along with their resource. Kopsia monoterpene alkaloids presented in various skeletons, but aspidofractinines, eburnamines, and chanofruticosinates are the three major backbones. Mersinines and pauciflorines are new chemical classes of monoterpene alkaloids. With the rich content of monoterpene alkaloids, Kopsia constituents were also the main objects in pharmacological studies since the plant extracts and isolated compounds were proposed for anti-microbial, anti-inflammatory, anti-allergic, anti-diabetic, anti-manic, anti-nociceptive, acetylcholinesterase (AChE) inhibitory, cardiovascular, and vasorelaxant activities, especially cytotoxicity.

Monoterpene alkaloids (466 isolated compounds) are major components, and anticancer activity is characteristic of Kopsia constituents.

Charantoside L, A New Cucurbitane-Type Glycoside from Momordica charantia L. with α-Glucosidase Inhibitory Activities

A new cucurbitane-type glycoside (1) and two known compounds (2-3) were isolated from the ethanol extract of the fruits of Momordica charantia L. Their chemical structures were determined as (19 S,23 E)-5 β­,19-epoxy-19-methoxycucurbita-6,23-diene-3 β,25-diol 3 -O-β-D-allopyranoside (1), goyaglycoside d (2), and (19 S,23 E)-5 β,19-epoxy-19-methoxycucurbita-6,23-diene-3 β,25-diol (3) on the basis of the extensive spectroscopic methods, including 1D, 2D NMR, HRESIMS, and in comparison with the reported data. Compounds 1 to 3 were evaluated for α-glucosidase inhibitory effects. Compounds 1 and 2 showed anti α-glucosidase activity with IC50 values of 134.12 ± 11.20 and 163.17 ± 13.71 µM, respectively, compared with the positive control, acarbose, IC50 160.99 ± 14.30 μM. Compounds 2 and 3 were first isolated from plant M. charantia growing in Vietnam.