Hit-Identification to Novel Antileishmanial Agents from a β-Pinene Scaffold: from Synthesis to In Vitro Evaluation and In Silico SAR/ADMET Profiling

High Resolution Image Download MS PowerPoint Slide β-Pinene, a low-cost natural product derived from agricultural waste, has shown in vitro activity against Leishmania amazonensis, but its use is hindered by unfavorable pharmacokinetic properties. Herein, we report a straightforward two-step synthesis of β-pinene-derived hydroxysulfides followed by an in vitro evaluation of their antileishmanial activity, cytotoxicity profile in mammalian cells, and in silico studies of structure–activity relationship (SAR) and ADMET properties. Initially, β-pinene was converted into its epoxide, the key intermediate of the series, through both chemoenzymatic and nonchemoenzymatic approaches. Then, we studied the thiolysis reaction by screening a series of bases and solvents. The use of NaOMe in methanol afforded the β-hydroxysulfide in 81% yield. This strategy afforded 16 novel derivatives bearing alkyl and (hetero)aryl substituents, with isolated yields ranging from 19 to 91%. The antileishmanial activity with promastigote cells showed that 11 compounds reduced parasite viability to 15.9). SAR analysis revealed key physicochemical features associated with activity, highlighting the importance of lipophilicity, polar surface area, and cLogP in promoting parasite membrane penetration. Meanwhile, in silico ADMET supported their drug-likeness since no mutagenic, cardiotoxic, or hepatotoxic potential was predicted, encouraging further in vivo and mechanistic studies.