Antifungal Activity of New Diterpenoid Alkaloids Isolated by Different Chromatographic Methods from Delphinium peregrinum L. var. eriocarpum Boiss

Abstract

This paper aimed to investigate the potential antifungal influences of new alkaloids from Delphinium peregrinum L. var. eriocarpum Boiss. New Diterpenoid alkaloids Delcarpum (1), Hydrodavisine (4) and known alkaloids Peregrine (2), Delphitisine (3) were isolated by different chromatographic methods from the aerial parts of D. Peregrinum eriocarpum Boiss, which grows in Syria. The structures of alkaloids were proposed based on 1D NMR spectroscopy 1H-NMR, 13C-NMR, DEPT-135, DEPT-90, 2D NMR spectroscopy DQF-COSY, HMQC, EI-Ms mass spectrum, and IR spectroscopic measurements. The antifungal activity of the isolated alkaloids was evaluated against different dermatophyte fungal isolates compared with fluconazole. In the case of Peregrine (2) the minimum inhibitory concentrations(MICs) recorded 128–256, 32–64, and 32 for Epidermophyton floccosum, Microsporum canis, and Trichophyton rubrum, respectively, compared to 32–64, 16, and 32 μg/mL in the case of fluconazole, respectively. The MICs recorded on application of the four alkaloids mixture were 64, 32, and 16 in the case of E. floccosum, M. canis, and T. rubrum, respectively, which were significantly lower than that measured for each of the individual alkaloid and were compatible for fluconazole. In conclusion, MICs of the tested alkaloids showed a variable potential effect on the investigated fungal isolates. Peregrine (2) was the most effective alkaloid, however, the application of the mixture of alkaloids induced significant synergistic activity that was more pronounced than the application of individual ones.

Chemistry, biological activities and toxic effects of alkaloidal constituents of genus Delphinium - A mini review

“…Alhalil and colleagues did another antifungal study of the aerial parts of Delphinium species. It was reported that isolated diterpenoid alkaloids including Hydrodavisine, Delcarpum, Delphitisine, and Peregrine from D. Peregrinum eriocarpum revealed antifungal activity (68). Kolak et al isolated eight norditerpene alkaloids from the root extracts of D. linearilobum.…”

Antimicrobial Diterpenes: Recent Development From Natural Sources

“…Compound 179 was the most effective among the four diterpenoids with MIC levels ranging between 128 and 256, 32–64, and 32 g/ml for Epidermophyton floccosum , Microsporum canis , and T. rubrum , respectively, compared to 32–64, 16, and 32 μg/ml in the case of standard fluconazole. Interestingly, a mixture of the four alkaloids had significantly lesser MIC (16–64 μg/ml) and MFC (64–258 μg/ml) levels compared to each individual alkaloid, which hints at the synergistic activity of these plant compounds against microorganisms ( Alhilal et al, 2021 ).…”

Exploring the Biomedical Potential of Terpenoid Alkaloids: Sources, Structures, and Activities

“…Compounds 102-106 have oxygen-containing groups at C-3 and C-6, whereas 105 and 106 contain a ketone group at C-3 [42,48,58]. Compounds 107-113 have oxygen-containing groups at C-6 and C-15 but no oxygen-containing group at C-3 [59]. Interestingly, the acetyloxy group of compound 113 at the C-6 position is β-oriented, uncommon in aconitine-type DAs [48,59].…”

“…Compounds 107-113 have oxygen-containing groups at C-6 and C-15 but no oxygen-containing group at C-3 [59]. Interestingly, the acetyloxy group of compound 113 at the C-6 position is β-oriented, uncommon in aconitine-type DAs [48,59]. • Lycoctonine-type C19-DAs (114-153)…”

“…Compared to atisine-type C20-DAs, hetisine-type C20-DAs feature a hexacyclic with an additional C14-C20 bond and N-C6 bond [82]. This category is the largest, and the newly discovered compounds 192-217 belong to this class of C20-DAs [37,59,68,83,84]. Among these, only compound 203, obtained from Aconitum, has a hydroxyl group at C-6 [85].…”