Isolation of bioactive limonoids from the fruits of Melia azedarach

Abstract

Two previously undescribed limonoids, 1-O-benzoyl-3-O-deactylnimbolinin C (1) and a pair of epimers named toosendalactonins A and B (12a and 12b), together with ten known compounds (2−11) were isolated from the fruits of Melia azedarach L. Their structures were determined by extensive spectroscopic methods, including 1D-, 2D-nuclear magnetic resonance, and mass spectrometry. All the isolated compounds were evaluated for their nitric oxide (NO) inhibition in lipopolysaccharide-activated microglia and nerve growth factor (NGF) production in astrocytes. Compounds 1−2 and 5−8 significantly inhibited NO production, which is comparable to the positive control, L-NMMA. Previously undescribed limonoid, compound 12, and two known limonoids, munronin K (3) and 12-O-methyl-1-O-deacetyl-nimbolinin B (4), showed the highest potency to increase the NGF production in C6 astrocytes.

Keywords:

• Melia azedarach
• Meliaceae
• limonoids
• anti-neuroinflammatory activity
• neuroprotective activity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was financially supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI, Grant No. HI15C0715), funded by the Ministry of Health and Welfare, Republic of Korea and National Research Foundation of Korea (NRF) grant [NRF-2017R1A6A3A11029000 and NRF-2018R1A6A1A03023718] funded by the Ministry of Education, Science and Technology, Republic of Korea.