## 1 Introduction  
Neglected tropical diseases (NTDs) are a collection of 20 diverse conditions that are prevalent in subtropical and tropical regions, where they affect more than 1 billion people who live in impoverished communities. Most of these diseases are parasitic, with high endemicity in developing countries in Africa, Asia, and the Americas [1]. Leishmananiasis and trypanosomatises are among the NTDs that occur in several sub-Saharan African countries [2]. These diseases are caused by trypanosomatids that interact with several mammals and insects to complete their life cycles. In general, _Trypanosoma brucei_ gambiense and _Trypanosoma brucei_ rhodesiense, _Trypanosoma cruzi_, and _Leishmania_ spp. are the parasites causing human African trypanosomiasis (HAT or sleeping sickness), Chagas disease, and cutaneous, mucocutaneous, and visceral leishmaniasisiasis, respectively. These kinetoplastid ailments are maladies of poverty that have received limited funding for the discovery and development of new tools [3]. The number of people infected by _T. cruzi_ is estimated between 6 and 7 million, and the disease is mostly transmitted by contact with the feces and/or urine of infected blood-sucking triatomine bugs (vector-borne transmission) [4]. The number of new cases of HAT has been reduced to the lowest level (<1000 new cases)in 2020, with 60-70 million people at risk of infection in thirty-six African countries. This disease is transmitted by infected steste flies [5]. Regarding leishmaniasisiasis, transmission occurs through bites by infected female phlebotomine sandflies, leading to estimates of approximately 700,000 to 1 million new cases annually [6]. Current treatments for human African trypanosomiasis include pentamidine, suramin, melarsoprol, elfornithine, and nifurtimox, whereas benznidazole and nifurtimox (Figure 1) are indicated for [PERSON] disease's treatment [4,5]. Approved therapies for leishmaniasisis's treatment include intravenous amphoteric B (liposomal) for VL and miltefosine (oral) for cutaneous leishmaniasisis (CL), mucocutaneous leishmaniasisis (ML), and visceral leishmaniasisis (VL) caused by specific species [7]. However, these medications suffer from the limitations of toxicity, requirements for parenteral administration, variable efficacy, and length of treatment schedules, in addition to the problem of drug resistance [2]. Therefore, there is a pressing need to search for safer anti-_trypanosomatidae_ therapies. Numerous studies have recently demonstrated the effectiveness of natural products vis-a-vis _trypanosomatidae_ at preclinical and clinical levels. Some of these studies focused on the identification of enzymes that are crucial for the survival and virulence of _trypanosomatidae_. These enzymes include farnesyl diphosphate synthase and squalene synthase [8]. In previous studies, 2-alkyl aminoethyl-1,1-bisphosphonate acids [9] and quinuclidine-based compounds [10,11] were reported to inhibit squalene synthase, whereas taxodione  
Figure 1: Chemical structures of commonly used anti-_Trypanosomatidae_ drugs. and arenarone inhibited the enzyme famesyl diphosphate synthase [12]. Unlike humans, these parasites (_T. cruzi_, _T. brucei_, and _Leishman_ spp.) use various types of sterols (e.g., ergosterol, 24-ethyl-cholesta-5,7,22-trien-3B-ol and its 22-dihydro analogs) in lieu of cholesterol in their cell membranes, so inhibiting the biosynthesis of endogenous sterol might be an essential therapeutic target [13]. The identification of inhibitors of these crucial enzymes might afford potentially active anti-_Tympanosomatidae_ hit compounds that can serve as starting points for the discovery of new treatments against leishmaniasises and trypanosomiasises. Thus, reviews or monographs are needed to summarize and discuss the latest information regarding the possibility for inhibitors of farnesyl diphosphate synthase and squalene synthase to impede the growth of _T Trypanosoma_ and _Leishman_ species. To date, only a few reports [13,14] have previously been published on this topic.