Citrus hystrix (kaffir lime). Ussually not available. Not that I can find them, or afford them anyway. The kaffir lime. High in vitamin C with many medicinal benefits when using properties found in the leaf itself.
Other key alkaloids and terpines such as citronellol, limonene, nerol.
The kaffir or any lime, can be a great blood alkline booster as well, or for pairing with Thai cuisine.