The Composition and Biochemical Properties of Strophantus (Apocynaceae), with a Focus on S. sarmentosus

The genus Strophantus belongs to the Apocynaceae family of flowering plants which grows primarily in tropical Africa. The plants are widely used in traditional herbal medicine. S. sarmentosus, in particular, is used for the treatment of, e.g., joint pain and rheumatoid arthritis, wound infections, head lice, diarrhea, snake bite, and eye conditions. Despite its widespread use, dedicated research characterizing its bioactive plant components is scarce. Investigations have focused mainly on its cardenolides because of their cardioactivity and historical use as cardiotonic. There are also studies concerning the antibacterial, antioxidant, and anti-inflammatory activity of plant extracts. This review summarizes the present knowledge surrounding the biochemical and analytical research on Strophantus, in general, and S. sarmentosus, in particular, and describes the current state of the field based on the available scientific literature.

Pattern of bioterrorism in ancient times: lessons to be learned from the microbial and toxicological aspects

The current research aimed to analyze the history of bioterrorism in antiquity and to adapt the data to modern medical knowledge. To this end, a thorough evaluation of the literature related to the ancient history of bioterrorism and modern data was done using the Web of Sciences, Science Direct, Scopus, PubMed, and Google Scholar. Results showed that knowledge of bioterrorism has existed since antiquity in different civilizations. Biological and toxicological agents were used as an instrument of legal execution, as a warfare tool in battles, or to eliminate political rivals across nations. Ancient people researched bioterrorism to apply it against enemies and at the same time provide countermeasures in favor of themselves and allies. Despite the existence of the principles of bioterrorism since ancient times, adaptation of the data to modern research can assist in planning countermeasure efforts, preventive actions, and treatments in the framework of modern counterterrorism medicine.

Bulbous Plants Drimia: "A Thin Line between Poisonous and Healing Compounds" with Biological Activities

Drimia (synonym Urginea) plants are bulbous plants belonging to the family Asparagaceae (formerly the family Hyacinthaceae) and are distinctive, powerful medicinal plants. Just some species are indigenous to South Africa and have been traditionally utilized for centuries to cure various diseases and/or ailments. They have been recognized among the most famous and used medicinal plants in South Africa. Traditionally, the plants are used for various illnesses such as dropsy, respiratory disease, bone and joint complications, skin disorders, epilepsy and cancer. A number of studies have reported biological properties such as antiviral, antibacterial, antioxidant and anti-inflammatory, immunomodulatory, and anticancer activities. Their bulbs are a popular treatment for colds, measles, pneumonia, coughs, fever and headaches. However, some plant species are regarded as one of the six most common poisonous plants in Southern Africa that are toxic to livestock and humans. Due to the therapeutic effects of the Drimia plant bulb, research has focused on the phytochemicals of Drimia species. The principal constituents isolated from this genus are cardiac glycosides. In addition, phenolic compounds, phytosterols and other phytochemical constituents were identified. This study constitutes a critical review of Drimia species' bioactive compounds, toxicology, biological properties and phytochemistry, advocating it as an important source for effective therapeutic medicine. For this purpose, various scientific electronic databases such as ScienceDirect, Scopus, Google Scholar, PubMed and Web of Science were researched and reviewed to conduct this study. Despite well-studied biological investigations, there is limited research on the toxic properties and the toxic compounds of certain Drimia species. Searching from 2017 to 2021, Google Scholar search tools retrieved 462 publications; however, only 3 investigated the toxicity and safety aspects of Drimia. The aim was to identify the current scientific research gap on Drimia species, hence highlighting a thin line between poisonous and healing compounds, dotted across numerous publications, in this review paper.

Cardenolides: Insights from chemical structure and pharmacological utility

Cardiac glycosides (CGs) are a class of naturally occurring steroid-like compounds, and members of this class have been in clinical use for more than 1500 years. They have been used in folk medicine as arrow poisons, abortifacients, heart tonics, emetics, and diuretics as well as in other applications. The major use of CGs today is based on their ability to inhibit the membrane-bound Na⁺/K⁺-ATPase enzyme, and they are regarded as an effective treatment for congestive heart failure (CHF), cardiac arrhythmia and atrial fibrillation. Furthermore, increasing evidence has indicated the potential cytotoxic effects of CGs against various types of cancer. In this review, we highlight some of the structural features of this class of natural products that are crucial for their efficacy, some methods of isolating these compounds from natural resources, and the structural elucidation tools that have been used. We also describe their physicochemical properties and several modern biotechnological approaches for preparing CGs that do not require plant sources.

Effect of extraction, microbial fermentation and storage on the cardenolide profile of Strophanthus kombé Oliv. seed preparations

Strophanthus extracts containing cardioactive cardenolides are still applied in European complementary medicine for the treatment of heart diseases. However, the cardenolide profile and the fate of individual compounds during extraction and storage are not well understood. Therefore, the objective of the present study was to characterize the cardenolide compound pattern in extracts of different polarity and their structural changes upon storage in aqueous fermented preparations. For this purpose, individual cardenolides were quantitated by a UHPLC-DAD validated method using an internal standard. Three different extraction protocols were compared: hydroethanolic extraction under reflux with and without previous defatting of the seed material and ultrasonic-assisted extraction at ambient temperature. Reflux extraction of non-defatted seeds showed maximum cardenolide yields. Differences in the cardenolide contents of seeds of the different origins Zimbabwe and Malawi were observed. The cardenolide profile and metabolization of individual compounds upon fermentation and storage of S. kombé seed extracts revealed that predominant cardenolides, mainly strophanthidin glycosides, changed upon storage over 12 months. Cardenolides exhibiting two or three saccharide moieties were degraded presumably by β-glucosidase activities, originating from the plant material or lactobacilli, releasing the corresponding monoglycosides. The latter were further degraded into the corresponding aglycones probably by acid hydrolysis as a result of lactic acid accumulation.