Myrrh trees (Commiphora) are useful things...

Most Commiphora have distinctive peeling bark, Eyasi Aug 2011.

Having last week given you the bad news about the biological warfare that plants with thorns are engaging in, I thought it only fair to share some tips that may help you stave off those tropical nasties threatening to kill you... So the good news is that some of those very same thorny trees that are out to get you also hold the cure in their sap. Traditional healers and many folk still living in the country have long known about the beneficial effects of the sap of Commiphora trees. Indeed, the earliest recorded use of Commiphora to treat infections goes back to 1100BC where Sumerians were recorded using myrrh (for that is what Commiphora is) to treat tooth infections and intestinal worms. It's use is also clear in the Bible, as one of the three famous gifts presented to the infant Jesus. Today it's still commonly used in village communities to treat an endless list of infections and maladies, and it's also pretty good as a mosquito repellant if you need emergency cover!

Commiphora sap flows freely from wounds and is extremely useful!

Until recently, however, there'd been very few scientific studies of the efficacy of Commiphora in treating various diseases. Making up for this, a whole suite of papers have been published in the last month or two testing various anti-bacterial and anti-viral properties of a range of Commiphora species, and the good news is that they really do work (that's not always guaranteed with traditional medicines...)! The study I like best is actually on anti-viral activity and was carried out by scientists here in Tanzania - it's my favourite because anti-viral activity (rather than anti-bacterial) is really rather rarely studied. Anti-bacterial activity is easy to measure - you grow your bacteria on something they like, then drop your plant juices in place and watch whether the bacterial colonies die or not (and they do - even more so if you mix it with frankensense oils, it seems). Anti-viral properties are much harder to measure and Bakari and colleagues tested this using chicken eggs infected with Newcastle disease. Newcastle disease is a viral disease of birds and the authors injected it into developing eggs. This would normally lead to almost 100% death of the developing embryo (as observed within two days in the control groups in this study), but they also injected various Commiphora juices (from leaves, sap, etc.) into some of the eggs at various concentrations. And in many of these eggs, the chicks lived and hatched. In fact, for the resin and bark treatments at intermediate concentration, none of the developing chicks died, and when many of them hatched they showed no antibody response to the virus, suggesting the Commiphora juices had killed the virus before the embryo mounted any immune response. At the highest concentrations some embryos did die, presumably as the Commiphora juice became toxic to the animal itself. Still, a very impressive demonstration of how good raw Commiphora is as an anti-viral agent.

Commiphora flower August 2011, Mwiba Ranch

The fruits are often in the dry season - August 2011, Mwiba Ranch

Commiphora is most abundant in the drier, more arid savanna, where thickets can develop mixed with various Vachellia and Senegalia species (are we really going to have to change the name of this habitat from Acacia-Commiphora woodland now?!) and form an interesting habitat for a number of species not often seen on safari - Lesser Kudu like these thickets, so too do Gerenuk and Fringe-eared Oryx. I have to say, I don't think any of these animals feed on Commiphora particularly (though I'm sure they'll eat the fruits), because the reason the sap is toxic to bacteria and viruses is simple: it's yet another plant defence. And a very effective one too (though they still have to combine it with thorns!) - most things that do eat them eat the young leaves that come just before the rainy season when they're still poorly defended. Indeed, elephants seem to dislike them so much that they'll selectively weed them out of the landscape, favouring Vachellia , pushing over Commiphora trees but not eating them at all. The fruits, however, are an important food item for lots of species, particularly of birds. Most Commiphora fruit (and flower) in the dry season when there's relatively little food on offer in the semi-arid savanna, so you can sometimes find busy flocks of birds concentrated on fruiting Commiphora trees - barbets are very fond of them and if there are Vulturine Guineafowl in the area you're bound to see them feeding under the tree. Interesting habitats, for sure.

Hadzabe near Lake Eyasi use Commiphora to light fires

You can also make some money from Commiphora - myrrh (from Commiphora myrrha) is fetching £10 per 100g in the UK, other species are also useful, and if you're caught without a match it's the preferred wood of many for the base when lighting a fire by friction, being nice and soft. All in all, a very handy plant to have around. So, don't be like Hemingway's Harry and allow yourself to die of an infected thorn wound, get out there, find some Commiphora sap and disinfect!

Main references:

Bakari, G., Max, R., Mdegela, R., Phiri, E., & Mtambo, M. (2012). Antiviral activity of crude extracts from Commiphora swynnertonii against Newcastle disease virus in ovo Tropical Animal Health and Production DOI: 10.1007/s11250-012-0076-6