Pyran is an oxygen-containing heterocyclic moiety, which exhibits an array of pharmacological properties. Pyran is also one of the important structural subunits found widely in natural products, e.g. coumarins, benzopyrans, sugars, flavonoids, xanthones, etc. The diverse anticancer capabilities of pyrans have been additionally evidenced by the fact that this heterocycle has recently been a focal point for researchers worldwide. This review provides a summary of pyran-based anticancer compounds, with emphasis on the past 10 years. It focuses on advancements in the field of naturally occurring pyrans as anticancer agents. The discussion also includes structure–activity relationships, along with the structures of the most promising molecules, their biological activities against several human cancer cell lines, as well as mechanistic insights discovered through the pharmacological evaluation and molecular modeling of pyran-based molecules. The promising activities revealed by these pyran-based scaffolds undoubtedly place them at the forefront for the discovery of prospective drug candidates. Thus, they could therefore be of great interest to researchers working on the synthesis of antitumour drug candidates.

Computer-aided drug design (CADD) often involves virtual screening (VS) of large compound datasets and the availability of such is vital for drug discovery protocols. We assess the bioactivity and “drug-likeness” of a relatively small but structurally diverse dataset (containing >1,000 compounds) from African medicinal plants, which have been tested and proven a wide range of biological activities. The geographical regions of collection of the medicinal plants cover the entire continent of Africa, based on data from literature sources and information from traditional healers. For each isolated compound, the three dimensional (3D) structure has been used to calculate physico-chemical properties used in the prediction of oral bioavailability on the basis of Lipinski’s “Rule of Five”. A comparative analysis has been carried out with the “drug-like”, “lead-like”, and “fragment-like” subsets, as well as with the Dictionary of Natural Products. A diversity analysis has been carried out in comparison with the ChemBridge diverse database. Furthermore, descriptors related to absorption, distribution, metabolism, excretion and toxicity (ADMET) have been used to predict the pharmacokinetic profile of the compounds within the dataset. Our results prove that drug discovery, beginning with natural products from the African flora, could be highly promising. The 3D structures are available and could be useful for virtual screening and natural product lead generation programs.

Computer-aided drug design (CADD) often involves virtual screening (VS) of large compound datasets and the availability of such is vital for drug discovery protocols. This paper presents an assessment of the “drug-likeness” and pharmacokinetic profile of > 2,400 compounds of natural origin, currently available in the recently published StreptomeDB database. The evaluation of “drug-likeness” was performed on the basis of Lipinski’s “Rule of Five”, while 46 computed physicochemical properties or molecular descriptors were used to predict the absorption, distribution, metabolism, elimination and toxicity (ADMET) of the compounds. This survey demonstrated that, of the computed molecular descriptors, about 28% of the compounds within the StreptomeDB database were compliant, having properties which fell within the range of ADMET properties of 95% of currently known drugs, while about 44% of the compounds had ≤ 2 violations. Moreover, about 50% of the compounds within the corresponding “drug-like” subset showed compliance, while >83% of the “drug-like” compounds had ≤ 2 violations. In addition to the previously verified range of measured biological activities, the compounds in the StreptomeDB database show interesting DMPK profiles and hence could represent an important starting point for hit/lead discovery from natural sources. The generated data are available and could be highly useful for natural product lead generation programs.

Traditional medicine caters for about 80% of the health care needs of many rural populations around the world, especially in developing countries. In addition, plant-derived compounds have played key roles in drug discovery. Malaria is currently a public health concern in many countries in the world due to factors such as chemotherapy faced by resistance, poor hygienic conditions, poorly managed vector control programmes and no approved vaccines. In this review, an attempt has been made to assess the value of African medicinal plants for drug discovery by discussing the anti-malarial virtue of the derived phytochemicals that have been tested by in vitro and in vivo assays. This survey was focused on pure compounds derived from African flora which have exhibited anti-malarial properties with activities ranging from “very active” to “weakly active”. However, only the compounds which showed anti-malarial activities from “very active” to “moderately active” are discussed in this review. The activity of 278 compounds, mainly alkaloids, terpenoids, flavonoids, coumarines, phenolics, polyacetylenes, xanthones, quinones, steroids, and lignans have been discussed. The first part of this review series covers the activity of 171 compounds belonging to the alkaloid and terpenoid classes. Data available in the literature indicated that African flora hold an enormous potential for the development of phytomedicines for malaria.

Vector-borne protozoan diseases represent a serious public health challenge, especially in the tropics where poverty together with vector-favorable climates are the aggravating factors. Each of the various strategies currently employed to face these scourges is seriously inadequate. Despite enormous efforts, vaccines—which represent the ideal weapon against these parasitic diseases—are yet to be sufficiently developed and implemented. Chemotherapy and vector control are therefore the sole effective attempts to minimize the disease burden. Nowadays, both strategies are also highly challenged by the phenomenon of drug and insecticide resistance, which affects virtually all interventions currently used. The recently growing support from international organizations and governments of some endemic countries is warmly welcome, and should be optimally exploited in the various approaches to drug and insecticide research and development to overcome the burden of these prevalent diseases, especially malaria, leishmaniasis, Human African Trypanosomiasis (HAT), and Chagas disease.