A comprehensive review of Pfaffia glomerata botany, ethnopharmacology, phytochemistry, biological activities, and biotechnology

ETHNOPHARMACOLOGICAL RELEVANCE

Pfaffia glomerata (Spreng.) Pedersen, Amaranthaceae, is found in South America, mainly in Brazil, where it is considered a species of great medicinal interest owing to its popular use as a tonic, aphrodisiac, anti-inflammatory, and analgesic. These properties can be attributed to the presence of the phytosteroid, 20-Hydroxyecdysone (β-ecdysone), the main compound found in its roots.

AIM OF THE REVIEW

This review aims to provide information about the botanical characteristics, ethnomedicinal uses, the phytochemistry, the biological activities, and the biotechnology of P. glomerata, an important species to local communities and groups researching medicinal plants of South America.

MATERIALS AND METHODS

The information available on P. glomerata was collected from scientific databases (ScienceDirect, PubMed/MEDLINE, SciELO, and Scopus) until June 7, 2023, using the search terms "Pfaffia glomerata", "Pfaffia glomerata (Spreng.) Pedersen", and "Brazilian ginseng". The review includes studies that evaluated the botanical, ethnopharmacological, and phytochemical aspects, biological properties, nutraceutical uses, and the application of biotechnology for improving the biosynthesis of metabolites of interest.

RESULTS

A total of 207 studies were identified, with 81 articles read in full. Seventy-six studies were included for qualitative synthesis. Overall, 40 compounds belonging to different classes are presented in this review, including ecdysteroids, triterpenes, saponins, flavonoids, anthraquinones, tannins, coumarins, alkaloids, and polysaccharides. Among them, flavonoids, anthraquinones, tannins, coumarins, and alkaloids were only putatively identified. β-Ecdysone, triterpenes, saponins, and polysaccharides are the chemical components most frequently identified and isolated from P. glomerata and possibly responsible for ethnopharmacological use and the biological activities of this species, with important in vitro and in vivo activities, such as anti-inflammatory, antidepressant, aphrodisiac, analgesic, gastroprotective, antioxidant, and prebiotic.

CONCLUSIONS

This review summarizes discussions about the P. glomerata species, highlighting its ethnopharmacological, chemical, biotechnological, and nutraceutical importance. New scientific studies on this species are encouraged in the search for new therapeutic molecules with pharmaceutical potential and nutraceutical applications.

Ecdysterone and Turkesterone-Compounds with Prominent Potential in Sport and Healthy Nutrition

The naturally occurring compounds ecdysterone and turkesterone, which are present in plants, including Rhaponticum carthamoides Willd. (Iljin), Spinacia oleracea L., Chenopodium quinoa Willd., and Ajuga turkestanica (Regel) Briq, are widely recognized due to their possible advantages for both general health and athletic performance. The current review investigates the beneficial biological effects of ecdysterone and turkesterone in nutrition, highlighting their roles not only in enhancing athletic performance but also in the management of various health problems. Plant-based diets, associated with various health benefits and environmental sustainability, often include sources rich in phytoecdysteroids. However, the therapeutic potential of phytoecdysteroid-rich extracts extends beyond sports nutrition, with promising applications in treating chronic fatigue, cardiovascular diseases, and neurodegenerative disorders.

The phytochemical, biological, and medicinal attributes of phytoecdysteroids: An updated review

The phytoecdysteroids (PEs) comprise a large group of biologically-active plant steroids, which have structures similar to those of insect-molting hormones. PEs are distributed in plants as secondary metabolites that offer protection against phytophagus (plant-eating) insects. When insects consume the plants containing these chemicals, they promptly molt and undergo metabolic destruction; the insects eventually die. Chemically, ecdysteroids are a group of polyhydroxylated ketosteroids that are structurally similar to androgens. The carbon skeleton of ecdysteroids is termed as cyclopentanoperhydro-phenanthrene with a β-side chain at carbon-17. The essential characteristics of ecdysteroids are a cis-(5β-H) junction of rings A and B, a 7-en-6-one chromophore, and a trans-(14α-OH) junction of rings C and D. Plants only synthesize PEs from mevalonic acid in the mevalonate pathway of the plant cell using acetyl-CoA as a precursor; the most common PE is 20-hydroxyecdysone. So far, over 400 PEs have been identified and reported, and a compilation of 166 PEs originating from 1998 has been previously reviewed. In the present review, we have summarized 212 new PEs reported between 1999 and 2019. We have also critically analyzed the biological, pharmacological, and medicinal properties of PEs to understand the full impact of these phytoconstituents in health and disease.

Assessing herbal products with health claims

Herbs, herbal extracts, or phytochemicals are broadly used as foods, drugs, and as traditional medicines. These are well regulated in Europe, with thorough controls on both safety and efficacy or validity of health claims. However, the distinction between medicines and foods with health claims is not always clear. In addition, there are several cases of herbal products that claim benefits that are not scientifically demonstrated. This review details the European Union (EU) legislative framework that regulates the approval and marketing of herbal products bearing health claims as well as the scientific evidence that is needed to support such claims. To illustrate the latter, we focus on phytoecdysteroid (PE)-containing preparations, generally sold to sportsmen and bodybuilders. We review the limited published scientific evidence that supports claims for these products in humans. In addition, we model the in silico binding between different PEs and human nuclear receptors and discuss the implications of these putative bindings in terms of the mechanism of action of this family of compounds. We call for additional research to validate the safety and health-promoting properties of PEs and other herbal compounds, for the benefit of all consumers.

The minor ecdysteroids from Ajuga turkestanica

INTRODUCTION

Ajuga turkestanica is a plant used in traditional medicine for its high ecdysteroid content, including the presence of the particularly active turkesterone, which possess efficient anabolic activity.

OBJECTIVES

To isolate and identify minor ecdysteroids present in a semi-purified plant fraction containing ca. 70% turkesterone.

MATERIAL AND METHODS

Multi-step preparative HPLC (combining RP- and NP-HPLC systems) was used to purify the different components present in the turkesterone fraction. Isolated compounds were identified by high-resolution mass spectrometry and 2D-NMR.

RESULTS

Fourteen ecdysteroids (including turkesterone and 20-hydroxyecdysone) were isolated. Seven of these, all bearing an 11α-hydroxy group, were previously unreported.

CONCLUSION

Ajuga turkestanica ecdysteroids are characterised by the abundance of 11α-hydroxylated compounds and by the simultaneous presence of 24C, 27C, 28C and 29C ecdysteroids. It is expected that even more ecdysteroids are to be found in this plant since the starting material for this study lacked the less polar ecdysteroids. The simultaneous presence of 20-hydroxyecdysone and turkesterone (its 11α-hydroxy analogue) as the two major ecdysteroids suggests that every ecdysteroid is probably present in both 11α-hydroxy and 11-deoxy forms.

Ecdysterone and its Activity on some Degenerative Diseases

Beside ecdysone (1), ecdysterone (2) is one of the most common 5β-cholest-7-en-6-one (ecdysteroid) derivatives, which, besides having a hormonal effect on invertebrates, possesses a number of favorable non-hormonal biological effects on mammals. The most interesting of these is that on degenerative diseases, one of which, up to now not clarified in detail, is the so-called adaptogenic effect (protection of the organism against adverse stress factors) associated with anabolic, gastroprotective, and antioxidant effects. A second group of favorable effects is the possibility of suppression of neurodegenerative processes and protection of the cardiovascular system (metabolic syndrome symptom suppression, antidiabetic activity, and protection of heart and blood vessels). Because of these properties, ecdysterone has the potential to be developed as a medicinal agent.

The Karlson Lecture. Phytoecdysteroids: what use are they?

Phytoecdysteroids are analogues of arthropod steroid hormones found in plants, where they deter predation by non-adapted predators. There is potential to exploit this to develop new strategies for pest control, either by using ecdysteroids as lead molecules for the design of novel pest control agents or by alteration of ecdysteroid levels/profiles in crop plants through plant breeding or genetic modification. However, it is other properties of phytoecdysteroids that have led to a rapid recent increase in scientific and commercial interest in these molecules. They are apparently non-toxic to mammals and a wide range of beneficial pharmacological (adaptogenic, anabolic, anti-diabetic, hepatoprotective, immunoprotective, wound-healing, and perhaps even anti-tumour) activities is claimed for them. In particular, this has led to a large (and unregulated) market for ecdysteroid-containing preparations for body-builders, sportsmen, and pets, among others. Ecdysteroids are also being considered as nutraceutical additives to food products. Further, ecdysteroids are good candidates as elicitors for gene-switch systems to be used in medical gene therapy and research applications. In this article, I review the applications of phytoecdysteroids and assess their future potential.

20-Hydroxyecdysone decreases weight and hyperglycemia in a diet-induced obesity mice model

The steroid hormone 20-hydroxyecdysone (20HE) is an essential signaling molecule that modulates molting response in insects and may function as a putative anabolic factor in vertebrate animals, although no mammalian 20HE receptor has been identified. Here we show that in H4IIE cell culture, 20HE treatment decreased expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase), reduced glucose production, and induced Akt2 phosphorylation sensitive to the phosphoinositide-3 kinase pathway-specific inhibitor LY-294002. Daily oral administration of 20HE (10 mg/kg for 13 wk) ameliorated obesity and insulin resistance in C57BL/6J mice fed a high-fat diet and produced a significant decrease of body weight gain and body fat mass compared with nontreated animals as demonstrated by dual-energy X-ray absorptiometry analysis. In addition, plasma insulin levels and glucose tolerance were significantly lowered by 20HE treatment. These changes were accompanied by the reduced hepatic expression of PEPCK and G6Pase and increased adiponectin production by visceral fat tissue. These studies demonstrate the anti-obesity and anti-diabetic effects of 20HE and begin to elucidate its putative cellular targets both in vitro and in vivo.

Practical uses for ecdysteroids in mammals including humans: an update

Ecdysteroids are widely used as inducers for gene-switch systems based on insect ecdysteroid receptors and genes of interest placed under the control of ecdysteroid-response elements. We review here these systems, which are currently mainly used in vitro with cultured cells in order to analyse the role of a wide array of genes, but which are expected to represent the basis for future gene therapy strategies. Such developments raise several questions, which are addressed in detail. First, the metabolic fate of ecdysteroids in mammals, including humans, is only poorly known, and the rapid catabolism of ecdysteroids may impede their use as in vivo inducers. A second set of questions arose in fact much earlier with the pioneering "heterophylic" studies of Burdette in the early sixties on the pharmacological effects of ecdysteroids on mammals. These and subsequent studies showed a wide range of effects, most of them being beneficial for the organism (e.g. hypoglycaemic, hypocholesterolaemic, anabolic). These effects are reviewed and critically analysed, and some hypotheses are proposed to explain the putative mechanisms involved. All of these pharmacological effects have led to the development of a wide array of ecdysteroid-containing preparations, which are primarily used for their anabolic and/or "adaptogenic" properties on humans (or horses or dogs). In the same way, increasing numbers of patents have been deposited concerning various beneficial effects of ecdysteroids in many medical or cosmetic domains, which make ecdysteroids very attractive candidates for several practical uses. It may be questioned whether all these pharmacological actions are compatible with the development of ecdysteroid-inducible gene switches for gene therapy, and also if ecdysteroids should be classified among doping substances.