Phloroglucinol α-Pyrones from Helichrysum: A Review on Structural Diversity, Plant Distribution and Isolation

Area of Science:

• Phytochemistry
• Natural Product Chemistry
• Medicinal Chemistry

Background:

• Helichrysum species (Asteraceae) are recognized for rich phytochemical diversity and traditional medicinal uses.
• Phloroglucinol-α-pyrone derivatives are a unique class of specialized metabolites with significant pharmacological activity.
• These compounds are found in Helichrysum species from Mediterranean, African, and Iranian regions.

Purpose of the Study:

• To consolidate phytochemical research on phloroglucinol-α-pyrone derivatives from Helichrysum species over the past five decades.
• To document and classify the identified compounds based on their structural features.
• To review the reported bioactivities and therapeutic potential of these metabolites.

Main Methods:

• Comprehensive literature search of phytochemical studies on Helichrysum species.
• Systematic documentation of isolated phloroglucinol-α-pyrone derivatives and their parent species.
• Classification of compounds into structural subclasses (monopyrones, dipyrones, phloroglucinol derivatives).
• Compilation of reported isolation yields and bioactivity data.

Main Results:

• Identification of 52 distinct phloroglucinol-α-pyrone derivatives from 11 Helichrysum species.
• Compounds are categorized into monopyrones, dipyrones, and other phloroglucinol derivatives.
• Isolation yields vary, with arzanol being the most studied compound.
• Reported bioactivities include anti-inflammatory, antimicrobial, antioxidant, and antiparasitic effects.
• Arzanol exhibits potent dual inhibition of microsomal prostaglandin E synthase-1 (mPGES-1) and 5-lipoxygenase (5-LOX).

Conclusions:

• This review provides a comprehensive overview of phloroglucinol-α-pyrone secondary metabolites from Helichrysum species.
• The documented compounds and their bioactivities offer valuable reference data for future research.
• Helichrysum-derived phloroglucinol-α-pyrones, particularly arzanol, hold significant promise for therapeutic applications.