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After heart disease, cancer continues to be the second most prevalent cause of death in the USA. Several chemotherapeutic treatments (drugs) are available for cancer that use powerful chemicals to kill the body's rapidly proliferating cells. However, recent research disclosed that many clinically viable anticancer drugs have been developed with the help of chemicals originating from plants. A number of phytochemicals isolated from plants possess rhamnopyranoses and some of them are acyl rhamnopyranoses. Encouragingly, such compounds were reported for their cell proliferation and migration inhibition activities against invasive human triple-negative breast cancer cells. In this study, four naturally occurring rhamnopyranose esters were checked against three cancer-related proteins (PDB IDs: 3TJM, 4OAR, and 5FGK) via molecular docking. Rhamnose compounds 3-6 showed better binding energy compared to the related standard drugs in use in the hospitals. Compound 6 was found highly potential against all the proteins (-8.5 to -11.3 kcal/mol). ADMET studies have also been discussed in this respect. This study indicated that natural rhamnopyranose esters could be used to stop the spreading of cancer cells like other reported sugar fatty acid esters (SFAEs).

The most widely used and accessible monosaccharides have a number of stereogenic centers that have been hydroxylated and are challenging to chemically separate. As a result, the task of regioselective derivatization of such structures is particularly difficult. Considering this fact and to get novel rhamnopyranoside-based esters, DMAP-catalyzed di-O-stearoylation of methyl α-l-rhamnopyranoside (3) produced a mixture of 2,3-di-O- (4) and 3,4-di-O-stearates (5) (ratio 2:3) indicating the reactivity of the hydroxylated stereogenic centers of rhamnopyranoside as 3-OH > 4-OH > 2-OH. To get novel biologically active rhamnose esters, di-O-stearates 4 and 5 were converted into six 4-O- and 2-O-esters 6–11, which were fully characterized by FT-IR, 1H, and 13C NMR spectral techniques. In vitro antimicrobial assays revealed that fully esterified rhamnopyranosides 6–11 with maximum lipophilic character showed better antifungal susceptibility than antibacterial activity. These experimental findings are similar to the results found from PASS analysis data. Furthermore, the pentanoyl derivative of 2,3-di-O-stearate (compound 6) showed better antifungal functionality against F. equiseti and A. flavus, which were found to be better than standard antibiotics. To validate the better antifungal results, molecular docking of the rhamnose esters 4–11 was performed with lanosterol 14α-demethylase (PDB ID: 3LD6), including the standard antifungal antibiotics ketoconazole and fluconazole. In this instance, the binding affinities of 10 (−7.6 kcal/mol), 9 (−7.5 kcal/mol), and 7 (−6.9 kcal/mol) were better and comparable to fluconazole (−7.3 kcal/mol), indicating the likelihood of their use as non-azole type antifungal drugs in the future.