3.2. Structure elucidation
The Fourier transform infrared spectroscopy (FTIR) spectrum revealed the presence of alkenes, alkanes, hydroxy and aldehyde groups as shown in Supplementary Figure. Similarly, from QTOF MS/MS data, m/z value of 349.093from which its molecular formula was determined to be C20H31NO4. This was in match with the molecular composition calculated by CHN analysis which gave a value of C: 0.687, H: 0.089, N: 0.040, O: 0.183. The molecular weight of the compound was later calculated to be 349.475 g/mol. The fragmentation data search from LC MS/MS spectrum did not match with any compound from the database (Figure 1). So, NMR data was required for structure solution. Hence different NMR spectra were made (Figure 2a and b.). The structure of the novel compound was resolved from the LC MS/MS data together with NMR spectra. From the 1HNMR and13C NMR spectra, the isolated compound was confirmed as (3S,5Z,7S,8Z)-7-amino-3,5-dihydroxy-2-methyl-13-[(1s,4s)-4-hydroxycyclohexa-2,5-dien-1-yl]trideca-5,8-dien-4-one (Figures 4 and 5 respectively). The 1H and13C NMR spectra pointed to a compound with long aliphatic chain and an open ring. Signals at δH 7.26 correlated with δC 67.62 suggested the presence of an NH group. δH at 2.46 to 2.62 and δC at 29.64 pointed to the presence of CH2 groups. δH at 1.25 to 1.67 indicated CH3 and 5.23 to 5.27 of C=CH2. This in correlation with δC 19.76 confirmed the long aliphatic chain. δC at 169.17 indicated a CH=CH and an the absence of any signal corresponding to aromatic ring inferred towards an open ring structure and named as Phormidin (Figure 3). Mass difference between fragments in MS/MS and from FTIR spectra confirmed the presence of the said groups. Structural search of the available literature revealed no reported compound and the purified compound was concluded to be entirely a novel one.