Comparative analysis of GC-MS of Isolona Engl. (Annonaceae) in Nigeria and the Cameroons

Abstract

The comparative assessment of six (6) Isolona species occurring in Nigeria and the Cameroons was undertaking using GC-MS analysis. The analysis was carried out with methanol extract and one hundred and seventy-six ( 176) phytoconstituents identified and scored at different retention times ranges from 3.22min in I. hexaloba (Pierre) Engl. & Diels. to 34.56min in I. campanulata Engl. & Diels.. The prominent compounds were scored in carboxylic and its derivates while the least compound was identified in alkyne. Highest M.wt. was 741.5 in I. congolana (De Wild.&T.Durand) Engl. & Diels. at retention time of 34.52 min and the lowest M.wt. was 84.15 in I. thonneri (De Wild.&T.Durand) Engl. & Diels. at retention time 3.44 min. Hexadecanoic acid, methyl ester formula C17H34O2 and M.wt of 270.4was scored in all the six species suggested a diagnostic characters for the genus Isolona. Quantitatively, the amount of the analytes isolated in all the species ranges from 0.1% in I. hexaloba to 59.36% in I. thonneri. Two UPGMA distant trees were constructed with RMSD and Euclidean index to illustrate the relationships among the Isolona species based on the difference chemical constituents. The distance tree revealed the separation of I. thonneri from all other species, also a sub-cluster tree of I. hexaloba, I. campanulata and I. zenkeri (Engl.) Dyer. was also constructed. The highest distance value level is 9.576 scored between I. thonneri and I. congolana while the highest similarity level was 2.911 scored in I. hexaloba and I. campanulata. The overlapping phyto-constituents characters revealed the closeness of the taxa studied, this invariably will update the existing data in the genus and ultimately in the family Annonaceae.