Objective: To analyze the accumulation of potential photo-protective compound groups, include phenol, flavonoid, and tannin in the leaf tissues of Sonneratia caseolaris (L.) Engler. Methods: The research used Sonneratia caseolaris (L.) Engler leaves as materials. The total of compound groups and photo-protective ability level of each tissue was measured using spectrophotometry, while detection of compound group accumulations in the leaf tissue were observed using histochemical assay. Results: Epidermis extract contained the highest content of total phenolic compounds (phenol, flavonoid, and tannin), followed by those of mesophyll and whole leaf. Moreover, Sun Protection Factor (SPF) value of epidermis was also higher than those of mesophyll and whole leaf, considering that there were no significant difference of SPF value between mesophyll and whole leaf. Result of histochemical assay of S. caseolaris fresh leaf sections showed that phenol, flavonoid, and tannin were highly accumulated in the epidermis and some parts of mesophyll. Conclusion: Potential photo-protective compound groups of S. caseolaris leaves were accumulated in epidermis and mesophyll. However, epidermis showed the highest level of potential photo-protective compound groups than those of other tissues. Photo-protective ability of epidermis also showed higher value than those of mesophyll.
Key words: Sonneratia caseolaris (L.) Engler, Secondary metabolite, Photo-protective, SPF, Leaf anatomy.