Sampangines

Fig. 8 Structures of sampangine, 3-methoxysampangine, and the transformed 4 -0-methyl-/S-glucopyranose and /S-glucopyranose conjugates [59]...

The detached leaf assays indicated that 625 ppm CAY-1 and sampangine provided effective protectant activity for disease control of anthracnose on the leaf surface (Table 1). These compounds were as effective as the commercial fungicide, azoxystrobin. 

Kluza, J., Mazinghien, R., Degardin, K., Lansiaux, A. and Badly, C. 2005. Induction of apoptosis by the plant alkaloid sampangine in human HL-60 leukemia cells is mediated by reactive oxygen species. European Journal of Pharmacology, 525(1-3) 32 0. 

Detached leaf assays provide us with the opportunity to evaluate new fungicides directly on the leaf surface in a dose-response format (Table 1). This assay allowed us to benchmark potential lead compounds such as CAY-1 and sampangine with a commercial standard (azoxystrobin) of known mode of action (Qo I inhibitor). The number of diseased lesions was used to determine effective concentrations needed for disease control. Lesion size is used to determine the relative effectiveness of the systemic activity that produced curative activity 24 hrs after inoculation. The detached leaf assay was also used to establish experimental field rates for future studies. Study of protectant activity indicated that 1250 ppm. CAY-1 or sampangine appeared to be an effective concentration for disease control of anthracnose on the leaf surface, or between 100-1000 times the concentration required for in vitro activity (Post, Table 1). 

Level Azoxystrobin Disease1 Phyto1 CAY-l Disease Phyto Sampangine Disease Phyto ... 

No systemic or translaminar activity was detected when azoxystrobin, CAY-1, or sampangine was applied 24 hrs after inoculation with C. fragariae (Pre, Table 1). 

Hufford and co-workers131 in a study of the metabolism of the antifungal copy-rine alkaloid sampangine, used micro-probe technology for the characterization of the alkaloid s major metabolite, which was sampangine /i-glucuronic acid (61). 

Microbial metabolism studies on sampangine have resulted in the isolation and characterization of two metabolites, sampangine-4 -0-methyl-P-glucopyranoside (SAMMl) and sampangine-P-glucopyranoside (SAMM2). 

Mammalian metabolism studies on sampangine gave two water-soluble conjugates. One of those conjugates, SAM MMl, has been identified as sampangine-P-glucuronic acid. 

In vitro antifungal activities evaluation for sampangine metabolites demonstrated comparable activities to sampangine. However, an in vivo efficacy study revealed that SAh 2 is inactive. The antifungal activity profile of sampangine metabolites led us to conclude that metabolism per se is not the cause for the in vivo inactivity of sampangine, hence, further studies on the other pharmacokinetic parameters (bioavailability, distribution, clearance, etc.) will be necessary. 

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