Alphitol, a phenolic substance from Alphitonia zizyphoides which inhibits prostaglandin biosynthesis in vitro

The genus Alphitonia Reissek ex Endl. (Rhamnaceae): A review of its customary uses, phytochemistry and biological activities

ETHNOPHARMACOLOGICAL RELEVANCE

Alphitonia Reissek ex Endl. is a relatively small genus of the family Rhamnaceae. Plants of this genus are found predominantly in the tropical regions of Southeast Asia, Australia and the Pacific, with some species being widely distributed and others endemic to a region. Almost half of the species of the Alphitonia genus have been reported for their customary (traditional and contemporary) medicinal uses. This includes for the treatment of skin conditions, headache, stomachache, inflammation, and body pain such as joint pain and childbirth.

AIM OF THE REVIEW

The aim of this review is to provide the first comprehensive account on the customary uses including ethnomedicinal uses, and phytochemistry and biological activities of the Alphitonia genus, and to identify gaps in current knowledge and scope for future research of plants of this genus.

MATERIALS AND METHODS

Information relevant to the genus Alphitonia was collected by searching the scientific databases (SciFinder, Google Scholar, ACS publications, PubMed, Wiley Online Library and International Plant name Index). Species names were validated using the World Flora Online database (www.worldfloraonline.org).

RESULTS

Eight plants from the Alphitonia genus have been reported to be used as customary medicines, i.e. A. excelsa, A. ferruginea, A. franguloides, A. incana, A. neocaledonica, A. petriei, A. philippinensis and A. zizyphoides. A. excelsa, A. petriei, A. philippinensis and A. zizyphoides, have been shown to have biological activities that align with their customary uses, including antimicrobial, antioxidant and anti-inflammatory activities. Only five Alphitonia species reported for their medicinal customary uses have been explored for their phytochemistry, i.e. A. excelsa, A. neocaledonica, A. petriei, A. philippinensis and A. zizyphoides. Compounds identified from these plants include those that are well known for their medicinal importance. A. macrocarpa, A. whitei and A. xerocarpus have also been examined for their phytochemistry and have been found to have the same or similar bioactive compounds to those found in customarily used Alphitonia species. No biological activities or phytochemistry studies have been reported for the known customarily used medicinal plants A. ferruginea, A. franguloides and A. incana.

CONCLUSIONS

This review highlights the customary uses, biological activities and phytochemistry of plants of the Alphitonia Reissek ex Endl. genus and highlights the significance of the knowledge systems of Indigenous peoples. Of the plants that have been researched for their biological activities and phytochemistry, there is good correlation with these properties and their customary medicinal uses. However, over half of the plants of the Alphitonia genus, including those that are already reported in the public domain for their customary medicinal uses, have had none or limited biological activities or phytochemistry studies conducted. While only eight species of the Alphitonia genus have been reported as customary medicines, other Alphitonia species also possess medicinally important compounds, and it is possible that they are customary medicines but their uses have not been shared publicly by the Indigenous knowledge custodians. There is clearly much scope for further investigation of this genus with regards to their ethnomedicinal uses and therapeutic potential.

Anti-Inflammatory Activities of Betulinic Acid: A Review

Inflammatory diseases have a high prevalence and has become of great interest due to the increase in life expectancy and the costs to the health care system worldwide. Chronic diseases require long-term treatment frequently using corticosteroids and non-steroidal anti-inflammatory drugs, which are associated with diverse side effects and risk of toxicity. Betulinic acid, a lupane-type pentacyclic triterpene, is a potential lead compound for the development of new anti-inflammatory treatments, and a large number of derivatives have been produced and tested. The potential of betulinic acid and its derivatives has been shown in a number of pre-clinical studies using different experimental models. Moreover, several molecular mechanisms of action have also been described. Here we reviewed the potential use of betulinic acid as a promissory lead compound with anti-inflammatory activity and the perspectives for its use in the treatment of inflammatory conditions.

A Review on Preparation of Betulinic Acid and Its Biological Activities

Betulinic acid, a pentacyclic triterpene, is distributed in a variety of plants, such as birch, eucalyptus and plane trees. It shows a wide spectrum of biological and pharmacological properties, such as anti-inflammatory, antibacterial, antiviral, antidiabetic, antimalarial, anti-HIV and antitumor effects. Among them, the antitumor activity of betulinic acid has been extensively studied. However, obtaining betulinic acid from natural resources can no longer meet the needs of medicine and nutrition, so methods such as chemical synthesis and microbial biotransformation have also been used to prepare betulinic acid. At the same time, with the development of synthetic biology and genetic engineering, and the elucidation of the biosynthetic pathways of terpenoid, the biosynthesis of betulinic acid has also been extensively researched. This article reviews the preparation of betulinic acid and its pharmacological activities, in order to provide a reference for the research and utilization of betulinic acid.

Phenolic glycosides from Glycosmis pentaphylla

Three new phenolic glycosides, named as glycopentosides A-C (1-3), along with nine known compounds were isolated from the n-BuOH extract of stems of Glycosmis pentaphylla. Their structures were determined by using spectroscopic and chemical methods. Bioassay showed that compound 10 (tachioside) could inhibit nitric oxide production in lipopolysaccharides-stimulated RAW 264.7 cells with IC50 value of 12.14 μM.

HPLC profiling with at-line microdilution assay for the early identification of anti-fungal compounds in plants from French Polynesia

INTRODUCTION

The search for anti-fungal compounds has maintained a scientific interest notably due to existing difficulties in the treatment of mycoses and their increasing occurrence in hospitals.

OBJECTIVE

Development of a simple method to rapidly identify anti-fungal compounds in crude plant extracts based on a HPLC microfractionation approach combined with an at-line anti-Candida assay.

METHODS

The scale of the semi-preparative HPLC microfractionation was adapted to fit the sensitivity of the Candida albicans anti-fungal in a 96-well microdilution assay. This format is also compatible for MS and NMR dereplication of the active compounds.

RESULTS

Based on the screening of 12 crude extracts of plants from French Polynesia, three plants, which displayed various levels of anti-fungal activities, were selected to assess the efficiency of the HPLC anti-fungal profiling and the scale necessary for microfractionation. The same anti-Candida assay was performed on the HPLC microfractions collected using a generic profiling method. Analysis of active microfractions by MS and NMR issued from the most active extract enabled an efficient dereplication of the compounds responsible for the anti-fungal activity.

CONCLUSION

A generic HPLC anti-fungal profiling method was developed which revealed that only 50 mg of crude extract were sufficient for a rapid identification of compound(s) responsible for the anti-Candida activity. This approach was illustrated by the study of Alphitonia zizyphoides, a plant traditionally used to treat dermatomycoses.

Two new flavanols from Glycosmis pentaphylla

Two new flavanols, glycoflavanones A (1) and B (2), which were found to possess α-pyrone moiety, together with five known compounds 4'-O-methylgallocatechine (3), β-sitosterol (4), alphitol (5), 3,4-dimethoxy-5-hydroxy-trans-cinnamyl alcohol (6), and oxyresveratrol (7), were isolated from the stems of Glycosmis pentaphylla by normal-phase and reverse-phase silica gel column chromatography. Their structures were determined on the basis of chemical and spectroscopic analyses.

Chemistry, biological activity, and chemotherapeutic potential of betulinic acid for the prevention and treatment of cancer and HIV infection

3beta-Hydroxy-lup-20(29)-en-28-oic acid (betulinic acid) is a pentacyclic lupane-type triterpene that is widely distributed throughout the plant kingdom. A variety of biological activities have been ascribed to betulinic acid including anti-inflammatory and in vitro antimalarial effects. However, betulinic acid is most highly regarded for its anti-HIV-1 activity and specific cytotoxicity against a variety of tumor cell lines. Interest in developing even more potent anti-HIV agents based on betulinic acid has led to the discovery of a host of highly active derivatives exhibiting greater potencies and better therapeutic indices than some current clinical anti-HIV agents. While its mechanism of action has not been fully determined, it has been shown that some betulinic acid analogs disrupt viral fusion to the cell in a post-binding step through interaction with the viral glycoprotein gp41 whereas others disrupt assembly and budding of the HIV-1 virus. With regard to its anticancer properties, betulinic acid was previously reported to exhibit selective cytotoxicity against several melanoma-derived cell lines. However, more recent work has demonstrated that betulinic acid is cytotoxic against other non-melanoma (neuroectodermal and malignant brain tumor) human tumor varieties. Betulinic acid appears to function by means of inducing apoptosis in cells irrespective of their p53 status. Because of its selective cytotoxicity against tumor cells and favorable therapeutic index, even at doses up to 500 mg/kg body weight, betulinic acid is a very promising new chemotherapeutic agent for the treatment of HIV infection and cancer.