Ethnobotany and quality control of bioproducts: Sustainable management of natural resources in urban environments

• Medicinal plants have significant economic value in urban environments. • Bioproduct engineering takes microbiological quality into account. • The effectiveness of bioproducts depends on the preservation of biological properties. • Safety and efficacy depend on the preservation of secondary metabolites of interest. Burkina Faso has great potential in terms of medicinal plants. These plants have been used to treat many illnesses since time immemorial, both in rural and urban areas. Medicinal plants sold in urban areas are generally adulterated. Suspicions of ineffectiveness and toxicity by some users call into question the benefits of using these highly prized medicinal plants. In the light of an ethnobotanical survey on the use of medicinal plants in the city of Ouagadougou, thirteen medicinal plant parts were identified as the most widely used and of greatest economic interest to the sellers of these herbal products. Given the storage conditions of these medicinal plant parts in market stalls, it was important to carry out a quality control. The medicinal plant parts were collected and their equivalents were purchased from the stalls of three selected markets after the ethnobotanical survey. Samples of various origins had undergone comparative analysis for the microbiological quality of the plant extracts according to International Organization for Standardization 4832. The impact of storage conditions on the phytochemical composition and antioxidant properties through the Reduction of 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid), the Free radical scavenging power 1,1-diphenyl-2-picrylhydrazyl and the ferric reducing antioxidant power methods were also taken into account. The microbial enumeration test revealed an excellent quality of the medicinal plant parts harvested and preserved under laboratory conditions (AdT: 0.02± 0.0001 × 10 6 CFU/g) compared with those acquired from the various markets (Ad1: 73.07 ± 1.42 × 10 6 CFU/g). Adansonia digitata extracts from markets 1 and 3 revealed the absence of total polyphenols and tannins compared to samples harvested and processed under laboratory conditions. The best anti-radical capacity was recorded for the decoction extract of Piliostigma reticulatum stored under laboratory conditions with a value of 59.91 ± 0.25 µgAAE/100 mg. The storage conditions of medicinal plants had an impact on the content of secondary metabolites and, at the same time, on the antioxidant properties of plant extracts. A significant difference between the values of different parameters of samples from different environmental conditions allowed defining recommendations for better product quality. These results will help to improve the quality of medicinal plants sold in Ouagadougou.