Extracts From Grapefruit ( Citrus paradisi ) Peel via Microwave-Assisted and Conventional Extractions: Evaluation of Nosema Infection and Toxicity in Honey Bees


Kaya M. M., Tutun H., Vural N., Özmen Ö., Okuyan S.

Veterinary Medicine and Science, vol.12, no.3, pp.1-12, 2026 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 12 Issue: 3
  • Publication Date: 2026
  • Doi Number: 10.1002/vms3.70917
  • Journal Name: Veterinary Medicine and Science
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED)
  • Page Numbers: pp.1-12
  • Ankara Yıldırım Beyazıt University Affiliated: Yes

Abstract

ABSTRACT

Background and Objectives: This study aimed to assess the effects of grapefruit peel extract on bee health and its anti-nosema activity.

Methods: Conventional and microwave-assisted extractions of grapefruit peels were optimized by using the response surface method based on a central composite design approach. HPLC was used to determine the polyphenolic content of the optimal extracts. The effects of optimum extracts on honeybees were evaluated through acute (4%, 2%, 1%, 0.5%, and 0.25%) and chronic (2%, 1%, 0.5%, and 0.25%) toxicity tests, as well as longevity assessments (2%, 1%, 0.5%, and 0.25%). Furthermore, the effects of the extracts on intestinal health were evaluated by histopathological examination, and the anti-nosema activity of the optimum extracts (1%) was assessed.

Results: In the toxicity tests, histopathological examinations showed that the extracts had no adverse effects on midgut health. While a 10-day feeding with the optimized extracts did not show a significant difference in overall lifespan, the longevity study showed that bees given 1% of the conventional optimal extract survived longer than the control group. The optimal extracts did not produce high anti-nosema activity at the applied dose.

Conclusions: Optimized phenolic-rich extracts have mild health-promoting effects and may offer mild support against Nosema , encouraging further research into bee health and disease management.