Andiroba (Carapa guianensis)
Andiroba (Carapa guianensis) is a large tree in the mahogany family that grows up to 40m. The tree is common in the rich soils of the Amazon Basin and surrounding area. The tree has a soft, durable wood that is sought for lumber. The tree produce a four corned nut about 7-10cm across. The nut contains kernels from which oil is harvested.
Andiroba oil has been harvested and utilized by indigenous people of the region for centuries. It has been used to treat skin parasites like ticks. The oil is applied to injuries, bites, rashes, boils. Brewed into a tea it is also used to treat fevers, worms, and ulcers. 

The oil is also burnt in lamps and is reported to repel mosquitoes. Andiroba is a potent insect repellent (MIOT et al, 2004). However, currently used throughout Brazil for many things. It is commercially manufactured into anti-inflammatory, antimicrobial, and insecticidal products

Andiroba oil is primarily composed of fatty acids including oleic, palmitic, stearic, and linoleic acids. Linoleic acid is an essential fatty acid required for many biological pathways. However, it cannot be synthesized by animals it is obtained through diet only. It serves in cell signaling and is positively linked to skin health.
Andiroba bark, oil, and leaves also contains limonoids, including a novel type andirobin (ROY et al, 2006). Limonoids are currently being investigated for a variety of therapeutic effects such as antiviral, antifungal, antibacterial, antibacterial, antimalarial and chemotherapy. Some are also utilized as an insecticide.

Miot, H. A., et al. “Comparative study of the topical effectiveness of the Andiroba oil (Carapa guianensis) and DEET 50% as repellent for Aedes sp.” Rev. Inst. Med. Trop. Sao Paulo. 2004 Sep-Oct; 46(5): 253-6.

Roy, A., et al. “Limonoids: overview of significant bioactive triterpenes distributed in plants kingdom. Biol. Pharm. Bull. 2006; 29(2): 191-201.