On November 24, 2019, this column made a debut. How time flies! I want to seize this opportunity to say a big thank you to you, my wonderful and esteemed readers for your support. Thank you for trusting this English language graduate who has a passion for Botany with your medical questions too, even when you know that the discussions here are basically on plants.
Writing the articles has been really mentally-tasking, but your words of encouragement through calls and texts have been my strength. In the mood of celebration, let us eat cake! Yes, you heard me right. Though cake was not known in the Garden of Eden, let us eat a little as we celebrate this milestone. We shall return to our fruit and vegetable diet after the celebration! Thank you, once again, for your support; you are highly appreciated.
This week, we shall be discussing Morinda lucida. The mention of the name alone gives me goose bumps because of its bitterness! The bitter-tasting roots are popular in Nigeria as chewing sticks. It is an important plant in traditional medicine in West Africa and various trials have confirmed the effectiveness of several of its uses. The plant is powerfully astringent too. Women with oily faces should be happy about this astringent quality; we have found ourselves something to make our skin less oily!
Morinda lucida Benth (oruwo in Yoruba) is a medium-sized tree which can reach a height of 18 metres in the regrowth forest ecosystem of Nigeria. It is in the family Rubiaceae. The bark is grey, rough and brittle; it bleeds a yellow juice when slashed. The leaves are broadly elliptic to broadly ovate, acuminate at the apex, broadly cuneate or occasionally rounded at the base. The leaves bear 5-8 pairs of lateral nerves; the petiole is about 1.5 cm long. The inflorescence is a cluster of white flowers into heads on peduncles which are united in threes positioned opposite to single leaves at alternate nodes (see the picture).
The decoction of the leaves and bark of oruwo is the recipe for malaria. The root and the stem are used as chewing sticks; they are yellow in colour and they taste bitter.
Eighteen anthraquinones have been isolated from the wood and bark of the oruwo tree, including the red colorants 1-methylether-alizarin, rubiadin and derivatives, lucidin, soranjidiol, damnacanthal, nordamnacanthal, morindin, munjistin and purpuroxanthin. Two anthraquinols; oruwal and oruwalol, have also been found; these give a yellow colour and possibly are intermediates in the formation of anthraquinones. In addition to anthraquinones, tannins, flavonoids and saponosides have been isolated.
Extracts of the plant have shown anti-inflammatory, analgesic, anti-bacterial, anti-malarial, anti-hepatotoxic and hepato-protective (removes liver pollution and protects liver and gallbladder), vermicidal (kills intestinal worms) antipyretic (reduces fever), anti-thrombotic (prevents blood clot) antioxidant (fights free radicals) and cardio-protective (protects heart muscles) properties!
Leaf extracts have shown in vitro antimalarial activity against Plasmodium falciparum while in several other tests, anti-diabetic properties have been confirmed. Inhibiting effects on cancer tumours have also been reported. The leaves are used for cleaning and scouring items such as calabashes.
In Nigeria, Morinda lucida is one of the four most used traditional medicines against fever. Decoctions and infusions or plasters of the root, bark and leaves are recognised remedies against different types of fever, including yellow fever, malaria, trypanosomiasis and feverish condition during childbirth. The plant is also employed in cases of diabetes, hypertension, cerebral congestion, dysentery, stomach-ache, ulcers, leprosy and gonorrhoea. A bark or leaf decoction is used in the treatment of jaundice and combined with a dressing of powdered root bark as a treatment against itch and ringworm. The wood yields yellow to red dyes.
The root bark is used to dye textiles into scarlet red. On occasions of national grief or the death of a chief, the Ashanti people of Ghana dye cotton cloths red with the root bark. These clothes, called ‘kobene’, are worn as mourning dresses by official people and by the family of the deceased. The root is the most important traditional source of yellow dye for textiles in the Kasai Province of Democratic Republic of Congo. It can be used without a mordant. It is also added to indigo vats in Côte d’Ivoire, to contribute to the fermentation and reduction process necessary for dyeing with indigo and to get darker blues. In this process, it is often combined with leafy twigs of Saba comorensis.
For dyeing, the root bark or leaves are used fresh, pounded or chopped. For red colours, the fibres to be dyed must first be mordanted with tannin-containing plants and alum. For red and yellow colours, the dye baths are prepared by boiling the root bark or leafy twigs in water for one or two hours before filtering and plunging the textiles into the coloured liquid and boiling it again until the desired shade is obtained.
In the region of Kasongo in north-eastern DR Congo, young leaves of Morinda lucida are combined with leaves of a Philenoptera species (a source of indigo) to obtain a pale-green dye used in basket weaving. The wood is yellow (hence the name brimstone tree), darkening to yellow-brown in the sapwood and to dark brown in the heartwood. It is medium-weight and hard; it works and finishes well and it is durable, being resistant to fungi, termites and other insects. It is used for construction, mining props, furniture, canoes, poles etc. It is also used for fuel and excellent for making charcoal.
In a study reported in the Journal of Medicinal Plants, studies by Adeleye et al., titled ‘Traditional and medicinal uses of Morinda lucida’, it was revealed that the many benefits derived from Morinda lucida are owed to the high contents of vitamins A, K and E, alkaloids and other phytochemicals which are powerful antioxidant bioactive components like flavonoids which are effective as free radical scavengers, have anti-allergic, anti-inflammatory, anti-viral, anti-proliferative and anti-carcinogenic properties. Phenolics which are anti-ageing, anti-inflammatory, anti-atherosclerosis, anti-carcinogenic, cardiovascular protection and improvement in endothelial function as well as inhibition of angiogenesis and cell proliferation activities, steroids used as anti-bacterial and anti-plasmodium. Alkaloids, the most essential of the phytochemicals, are used as anti-parasitic agents.
According to another study reported in the Journal of Bacteriology and Parasitology by Momoh Johnson Oshiobugie et al., titled ‘GC-MS, AAS, antioxidant and antiplasmodial activities of methanolic leaf extract of Morinda lucida (Ewe Oruwo) in male swiss mice infected with Plasmodium berghei NK65’, the conclusion is that Morinda lucida possess antiplasmodial activity.
It is clear that Oruwo is rich in virtually all the classes of beneficial phytochemicals: vitamins, alkaloids, flavonoids, phenolics, steroids which can explain its anti-plasmodial, anti-parasitic, anti-viral, anti-carcinogenic, anti-proliferative and other health-beneficial uses. The most important use of oruwo was in the treatment of malaria, diabetes, hypertension, cerebral congestion, dysentery, stomach-ache, ulcers, jaundice, leprosy and gonorrhoea for a long time. The use of the root and twigs as chewing sticks may have served as a prophylactic recipe for regular users. Oruwo is more than a chewing stick!
Credit: Olufunke Faluyi, Punch