Red Ball Ginger (Zingiber zerumbet) Extracts-Enriched Soy Milk: Mitigation of Rheumatoid Arthritis-Related Symptoms and Lipid-Modulating Effects of Hyperlipidemia in the Experimental Animal Models

Zingiber zerumbet, commonly referred to as red ball ginger or pinecone ginger, is a perennial species of the family Zingiberaceae, native to India and Malaysia. It is primarily distributed throughout tropical Asia and the Pacific islands, where it naturally inhabits moist, shaded lowlands and hillsides. The plant is characterized by its distinctive pinecone-like inflorescences, formed by overlapping bracts that turn bright red upon maturity, enhancing its ornamental appeal. In Taiwan, Z. zerumbet is relatively rare, maintained through limited germplasm conservation or small-scale contract cultivation. In contrast, it is more widely recognized and utilized in regions such as India, China, and Malaysia. Beyond its horticultural value, Z. zerumbet is of notable ethnomedicinal interest; its rhizome has traditionally been used as a food flavoring and as a herbal remedy in folk medicine in India and Malaysia. In this study, the adult male 24 Sprague-Dawley (SD) rats (6 weeks old) with specific pathogen-free conditions were used in this study. In this experiment, all SD rats (n = 24) were divided respectively the normal control group (n = 8), the high-fat diet group (n = 8), and the Z. zerumbet group (n = 8). The high-fat feed (containing 0.2% cholesterol) was used to feed SD rats for 8 weeks to induce hyperlipidemia in the negative control group and the Z. zerumbet group; At the 5th week of the high-fat feed administration, the  rheumatoid arthritis (RA) was inducted in all animals in the high-fat diet group and the Z. zerumbet group. In the normal control group, animals had ad libitum access to reverse osmosis (RO) water throughout the experimental period.  In the high-fat diet group, each animal was administered soy milk daily via oral gavage at a volume of 10 mL/kg body weight (BW). In the Z. zerumbet group, red ball ginger (Z. zerumbet) powder was suspended in soy milk at a concentration of 150 mg/mL. Animals in the Z. zerumbet group received a daily dose of red ball ginger powder equivalent to 1,500 mg/kg BW.  Hyperlipidemia and RA animal models were applied and the evaluated items in hyperlipidemia and RA were analyzed. Blood were collected before hyperlipidemia was induced (D0) and blood was collected every week after hyperlipidemia was induced. The BW of SD rats were weighed weekly. The TG (triglyceride), TCHO (total cholesterol), HDL (high-density lipoprotein), and LDL (low-density lipoprotein) contents in blood were detected and analyzed at each experimental time point. In the Z. zerumbet group, supplementation with Z. zerumbet-enriched soy milk significantly reduced serum total cholesterol and LDL cholesterol levels compared to the high-fat diet group, approaching those of the normal control group. The elevated AST/ALT ratio observed in the high-fat diet group was attenuated by Z. zerumbet, suggesting improved liver function. Paw swelling and arthritis clinical scores induced by RA were also significantly reduced in the Z. zerumbet group, indicating anti-inflammatory potential. BW gain and food intake were not significantly affected by Z. zerumbet supplementation after RA induction. According to the experimental results, soy milk enriched with red ball ginger (Z. zerumbet) extracts shows potential for lowering blood lipids and alleviating RA in the high-fat diet-induced rat models. Therefore, Z. zerumbet-enriched soy milk may be considered a promising functional food candidate for modulating blood lipids and alleviating rheumatoid arthritis symptoms.