A quinoline alkaloid rich Quisqualis indica floral extract enhances the bioactivity

Abstract

A volatile alkaloid quinoline-4-carbonitrile (QCN) was isolated from the floral extract of Quisqualis indica. Major compounds were trans-linalool oxide (1.0, 4.5%), methyl benzoate (1.0, 4.0%), 2,2,6-trimethyl-6-vinyl-tetrahydropyran-3-one (7.4, 17.8%), 2,2,6-trimethyl-6-vinyl-tetrahydropyran-3-ol (1.0, 1.2%), (E,E)-α-farnesene (29.1, 16.1%), QCN (5.7, 1.3%) in live and picked flowers, respectively. Flower compositions were altered due to change in enzymatic reaction at the time of picking. Some rearrangements of oxygenated terpenoids occurred in the process of hydrodistillation to obtain essential oil. Chemical synthesis of QCN and its selectively reduced products derived from QCN were prepared through green reaction process. The catalytic modification of QCN has produced quinoline-4-methylamine; the later compound has shown enhanced bio-activities. QCN and floral extract (absolute) have shown potential anti-inflammatory and antioxidant activities. Besides, floral absolute has shown significant anti-inflammatory and antioxidant activities due to improved QCN (19.7%) content to synergize amongst terpenoids and benzenoids as compared to the essential oil with 1.1% of QCN.

GRAPHICAL ABSTRACT

Keywords:

• Quisqualis indica
• HS-SPME
• Essential oil
• Absolute
• Quinoline-4-carbonitrile
• Pd/Ac Catalyst
• Anti-inflammatory

Acknowledgements

We are grateful to Director, CSIR-CIMAP, Lucknow for providing necessary facility under Aroma Mission (HCP 0007). Authors are thankful to SERB, DST, New Delhi, India (EMR/2016/005359) for research funding and fellowship to Prashant Kumar, to Dr. Priyabrat Mohapatra, Head, Chemistry Department, C.V. Raman College of Engineering for catalyst characterization and Dr. Hariom Gupta, CSIR-CIMAP for NMR interpretation.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

DST, SERB (EMR/2016/005359); INDIA.