Phenolic Constituents of Medicinal Plants with Activity against Trypanosoma brucei

Abstract

Neglected tropical diseases (NTDs) affect over one billion people all over the world. These diseases are classified as neglected because they impact populations in areas with poor financial conditions and hence do not attract sufficient research investment. Human African Trypanosomiasis (HAT or sleeping sickness), caused by the parasite Trypanosoma brucei, is one of the NTDs. The current therapeutic interventions for T. brucei infections often have toxic side effects or require hospitalization so that they are not available in the rural environments where HAT occurs. Furthermore, parasite resistance is increasing, so that there is an urgent need to identify novel lead compounds against this infection. Recognizing the wide structural diversity of natural products, we desired to explore and identify novel antitrypanosomal chemotypes from a collection of natural products obtained from plants. In this study, 440 pure compounds from various medicinal plants were tested against T. brucei by in a screening using whole cell in vitro assays. As the result, twenty-two phenolic compounds exhibited potent activity against cultures of T. brucei. Among them, eight compounds-4, 7, 11, 14, 15, 18, 20, and 21-showed inhibitory activity against T. brucei, with IC 50 values below 5 µM, ranging from 0.52 to 4.70 µM. Based on these results, we attempt to establish some general trends with respect to structure-activity relationships, which indicate that further investigation and optimization of these derivatives might enable the preparation of potentially useful compounds for treating HAT.

Antileishmanial Activity and Immunomodulatory Effects of Tricin Isolated from Leaves of Casearia arborea (Salicaceae)

“…Vanillic acid ( 3 ) is a hydroxybenzoic acid derivative belonging to the class of phenolic compounds. These natural compounds have been particularly studied for their potential as anti‐parasitic agents . Although no effectiveness against L. infantum intracellular amastigotes could be observed in our assays, previous studies demonstrated the antiparasitic effect of vanillic acid ( 3 ).…”

The Correlation between Chemical Structures and Antioxidant, Prooxidant, and Antitrypanosomatid Properties of Flavonoids

“…This disease is transmitted by tsetse fly (genus Glossina ), a vector which is only found in tropical Africa, this explains the T. brucei geographic restriction [5, 6]. …”

Trypanosoma brucei Inhibition by Essential Oils from Medicinal and Aromatic Plants Traditionally Used in Cameroon (Azadirachta indica, Aframomum melegueta, Aframomum daniellii, Clausena anisata, Dichrostachys cinerea and Echinops giganteus)

“…In this regard, the African flora represents a valuable source of anti-infectious compounds to be exploited as drugs [ 5 , 6 , 7 ]. In the fight against Trypanosoma infections, new therapeutic options can be provided by plant extracts, essential oils, and plant-borne compounds [ 6 , 8 , 9 , 10 ]. Essential oils are volatile mixtures distilled from aromatic plants and composed of several dozens of components such as terpenoids, phenylpropanoids, and aliphatic compounds [ 11 , 12 ].…”