This study was designed to examine the chemical compositions of scent volatiles and antioxidant activities of Polianthes tuberosa L. flower extract in six different solvents. The main constituents of the volatile components were benzyl benzoate, methyl 2-amino benzoate, methyl isoeugenol, isoeugenol, benzyl salicylate, methyl salicylate, geraniol and 1,8-cineole. Total phenolic content of floral extracts in water, methanol, ethanol, ethyl acetate, hexane and dichloromethane were found to be 0.094, 0.18, 0.14, 0.007, 0.004 and 0.110 mg gallic acid equivalent/mg fresh weight, respectively. The methanol soluble fraction showed highest values of antioxidant activity through DPPH and ABTS assays. Methanol extract effectively inhibits the non site-specific DNA strand breakage caused by Fenton’s reagents. Dichloromethane and aqueous fractions also exhibited high antioxidant capacities. Aqueous extract showed highest value in FRAP assay.

The in vitro antioxidant capacities of Polianthes tuberosa L. flower extracts

Two secoiridoid glucosides from Jasminum mesnyi

Profiling of volatile and non-volatile metabolites in Polianthes tuberosa L. flowers reveals intraspecific variation among cultivars.

The role of central carbon metabolism in the synthesis and emission of scent volatiles in tuberose flowers was revealed through measurement of changes in transcripts and metabolites levels. Tuberose or Agave amica (Medikus) Thiede & Govaerts is a widely cultivated ornamental plant in several subtropical countries. Little is known about metabolite networking involved in biosynthesis of specialized metabolites utilizing primary metabolites. In this study, metabolite profiling and gene expression analyses were carried out from six stages of maturation throughout floral lifespan. Multivariate analysis indicated distinction between early and late maturation stages. Further, the roles of sugars viz. sucrose, glucose and fructose in synthesis, glycosylation and emission of floral scent volatiles were studied. Transcript levels of an ABC G family transporter (picked up from the floral transcriptome) was in synchronization with terpene volatiles emission during the anthesis stage. A diversion from phenylpropanoid/benzenoid to flavonoid metabolism was observed as flowers mature. Further, it was suggested that this metabolic shift could be mediated by isoforms of 4-Coumarate-CoA ligase along with Myb308 transcription factor. Maximum glycosylation of floral scent volatiles was shown to occur at the late mature stage when emission declined, facilitating both storage and export from the floral tissues. Thus, this study provides an insight into floral scent volatiles synthesis, storage and emission by measuring changes at transcripts and metabolites levels in tuberose throughout floral lifespan.

Revealing floral metabolite network in tuberose that underpins scent volatiles synthesis, storage and emission

The flowers of Polianthes species were collected in the Thai Nguyen city, Viet Nam. Their volatile oil extracts were obtained via supercritical CO2 extraction and chemical compositions of the volatile oil part were subsequently analysed by GC-FID and GC/MS systems. Some major chemical compositions of volatile oil were identified as methyl 2-amino benzoate, isoeugenol, 1-Eicosene, indole, 5-octadecene, benzylbenzoate, diisobutylphthalate, 1-nonadecene, trans-farnesol. The chemical compositions of volatile oil of Polianthes sessiliflora (P. sessiliflora) and Polianthes longiflora (P. longiflora) species were being reported for the first time.The activities of total volatile oil extract of the Polianthes genus flowers against HeLa, A459, and Hep-2 cancer cell lines were evaluated.

A. M. El-Moghazy

Papers

Phytochemical studies on Polianthes tuberosa L.

Phytochemical studies on Jasminum mesnyi H.