Bioactive Phenylpropanoids, Phenolic Acid and Phytosterol from Landolphia owariensis P. Beauv Stringy Seed Pulp

Landolphia (P. Beauv.) genus: Ethnobotanical, phytochemical and pharmacological studies

The genus Landolphia (P. Beauv.) belongs to the Apocynaceae family with over 65 species distributed all over the tropical regions. This genus has a considerable number of documented medicinal, industrial, and ecologically beneficial effects. Therefore, this review is tailored towards the appraisal of the traditional significance, phytochemistry, and pharmacological activities of the genus Landolphia. This will help researchers understand future research trends by bridging the gaps between documented literature and contemporary uses. Relevant information was obtained from selection of scientific databases such as Web of Science, PubMed, Scopus, Google Scholar, ScienceDirect and Wiley. From documented literature, different parts of Landolphia have been used to improve fertility, lessen menstrual pain, boost sex libido, cure malaria and typhoid. Several classes of bioactive constituents such as terpenoids, phenolics, flavonoids, steroids, fatty acids, saponins, phytosterol and phenylpropanoid, volatile compounds, lignans and coumarins have been isolated from this genus. These secondary metabolites could be responsible for the reported antimicrobial, antimalarial, aphrodisiac, antioxidant, anti-inflammatory, antidiabetic and anticancer activities exhibited by this genus. The leaves, flower, bark and root of this genus have a wide range of essential nutrients and antinutrients which are essential for normal growth and development in living organisms. Despite all findings indicating the economical, industrial and pharmacological activities of Landolphia species, secondary metabolites and pharmacological potency of Landolphia of this genus are not adequately documented. Therefore, bioassay-guided isolation on the Landolphia extracts with proven biological activities should be prioritised in order to isolate pharmacophores with unique structural frameworks.

The genus Landolphia P.Beauv. (Apocynaceae): A comprehensive review on its ethnobotanical utilizations, pharmacology and nutritional potential

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Landolphia is an important resource for African traditional medicine. Among the 60 different accepted species, nearly every plant part of the genus (bark, fruit, latex, leaf, leaf sap, root, rootbark, twig) from 13 species is utilized by traditional healers around Africa. Accordingly, many pharmacological studies (42) were performed on the most common species (11).

AIM OF THE STUDY

This comprehensive literature review summarizes all publications dealing on one of the 60 plant species from the genus Landolphia. An overview about already performed analysis is given and important aspects and knowledge gaps are highlighted for the direction of future research activities.

MATERIALS AND METHODS

A systematic web search taking into account the major platforms Web of Science, Scopus, PubMed, SciFinder and Google Scholar was performed for the term Landolphia. All relevant datasets, published between 1804 and 2022, were ordered according to their topics in different sections and compared to each other. A network visualization of the keywords via VOS Viewer was additionally performed.

RESULTS

In total, 209 publications were retrieved from the search engines, mainly written in English. Predominant are ethnopharmacological studies, which identified 292 phytochemicals in plant parts of the whole genus. Diverse biological activities were detected in different plant extracts, and five species were determined as of special interest for the treatment of malaria. Further research topics identified are botanical aspects, ethnobotanical utilizations, ecological aspects, the potential as source for human and animal nutrition, the manufacturing of rubber, economic aspects, biomechanical studies and others. L. owariensis is the most studied plant as it is abundant in continental Africa.

CONCLUSIONS

This review serves as a database for upcoming research on the genus Landolphia and directs existing knowledge gaps. A wide range of chemical components are already identified, but their exact content in the respective plant parts and their biological activity remains mainly unknown. Utilization patterns from traditional medicine are only partially analyzed as demonstrated for the applications as aphrodisiac, to treat skin diseases or as antidiabetic. Nutritional analyses likewise focus on several species of Landolphia and lack for the wide range of known edible fruits. The demand for new natural products in terms of medicine, rubber and nutrition is still high and the genus Landolphia seems to be a promising resource covering many aspects at once.

Targeting Foam Cell Formation in Atherosclerosis: Therapeutic Potential of Natural Products

Foam cell formation and further accumulation in the subendothelial space of the vascular wall is a hallmark of atherosclerotic lesions. Targeting foam cell formation in the atherosclerotic lesions can be a promising approach to treat and prevent atherosclerosis. The formation of foam cells is determined by the balanced effects of three major interrelated biologic processes, including lipid uptake, cholesterol esterification, and cholesterol efflux. Natural products are a promising source for new lead structures. Multiple natural products and pharmaceutical agents can inhibit foam cell formation and thus exhibit antiatherosclerotic capacity by suppressing lipid uptake, cholesterol esterification, and/or promoting cholesterol ester hydrolysis and cholesterol efflux. This review summarizes recent findings on these three biologic processes and natural products with demonstrated potential to target such processes. Discussed also are potential future directions for studying the mechanisms of foam cell formation and the development of foam cell-targeted therapeutic strategies.