Sceletium tortuosum is a plant from South Africa purported to have mood enhancing and psychoactive properties. Little human research has been published with sceletium. See this link for natural ways to improve depression.

The use by the Khoisan of South Africa of Sceletium plants in psychoactive preparations has often been alluded to in the literature. However, much of it is fragmentary and contradictory. Apart from chewing the dried product, after "fermentation', there are reports of uses as tinctures for sedation and analgesia, chewing the material directly and smoking the residue after chewing. The symbolic connections of Sceletium with eland antelopes, the "trance animals' par excellence of the San hunter-gatherers is noted. There is no evidence to support the view that "kougoed' or Sceletium alkaloids are hallucinogenic. The alkaloid distribution in Sceletium and other members of the family Mesembryanthemaceae are considered. Chemical studies have indicated as many as nine alkaloids in Sceletium which fall into three distinct structural categories. Mesembrine, the alkaloid first isolated and named is not the dominant constituent of plants and is weakly narcotic. Evidence is assembled to suggest that traditional and contemporary methods of preparation serve to reduce levels of potentially harmful oxalates, which are found in Sceletium and other Mesembryanthemaceae.

Sceletium herb questions
Q. Do you have any experience of the herb sutherlandia sometimes referred to as 'African ginseng'? I started taking one 300mg tablet last week and I must say it has a very pleasant and relaxing effect. I note that I get a very good sleep with it. It reputedly has high levels of Gaba in it. There is another South African herb called sceletium which I have not tried but maybe you have. I would certainly value your opinion.
   A. I personally have not tried these African herbs but they sound interesting.