# Engineered Sporopollenin Exine Capsules for Colon-Targeted Delivery and Antioxidant Therapy of Pogostemon Oil in Ulcerative Colitis

## TL;DR

This study develops a colon-targeted delivery system using natural micro-capsules to improve the effectiveness of Pogostemon oil in treating ulcerative colitis.

## Contribution

A novel colon-targeted delivery system using sporopollenin exine capsules and calcium alginate for Pogostemon oil is developed.

## Key findings

- The system achieved over 69% encapsulation efficiency and 27.64 g/g adsorption capacity for Pogostemon oil.
- The formulation improved thermal and photostability of Pogostemon oil and showed pH-responsive release in intestinal conditions.
- In a mouse model, the system reduced UC symptoms and modulated inflammatory cytokines like IL-1β, IL-6, and IL-10.

## Abstract

Ulcerative colitis (UC) is an inflammatory bowel disease associated with oxidative stress. Pogostemon oil (PO) exhibits potent antioxidant and anti-inflammatory activities but is limited by high volatility and poor gastrointestinal stability. In this study, sporopollenin exine capsules (SECs) were engineered as natural micro-carriers for PO, achieving efficient encapsulation (η > 69%) and a high adsorption capacity (27.64 g/g). A pH-sensitive calcium alginate shell was subsequently applied to construct colon-targeted microspheres (Ca-Alg@PO-SECs). The resulting system improved the thermal and photostability of PO. In vitro dissolution assays confirmed the system’s pH-responsiveness, maintaining integrity under simulated gastric conditions while enabling localized release at intestinal pH. In a DSS-induced acute UC mouse model, Ca-Alg@PO-SECs effectively alleviated clinical symptoms, as evidenced by improved body weight, colon length, and disease activity index. At the inflammatory level, the formulation modulated key cytokines (IL-1β, IL-6, and IL-10). Overall, Ca-Alg@PO-SECs provides a biocompatible, colon-targeted delivery strategy that preserves the bioactivity of essential oils and offers a promising preclinical approach for localized UC therapy.