The term spice is often associated with hotness and pungency; in reality, though, only a few plants are suited to transmit a pungent quality to the food.

Furthermore, it is worth noting that the prototype of all hot spices, chile, originates from the New World and thus was not available in Europe, Asia, and Africa until the 16th century, although today, food of all continents cannot be imagined without it.

Hwentea has been used as a pepper substitute in Europe, but with regular imports of black pepper from India starting in the 16th century, it mostly disappeared. In later times, hwentea was only traded as a pepper substitute (or surrogate) in times of war and short supply; the last time, it was seen from after World War II till the 60ies of the previous century.  Hwentea also has the same function that is used as a spice. In the old days, hwentea was used as traditional medicine and for food. 

In West African cookbooks (Cameroon), the spice is referred to as kieng. In its origin, it has been found that hwentea has its root in tropical Africa (Ethiopia to Ghana), where both the species X. aethiopica and X. striata are used for local cooking. In South America, X. aromatica (burro pepper), has found similar applications among Brazilian Indios.

Xylopia aethiopica 

 The name Xylopia is a com­pression from Greek xylon pikron [ξύλον πικρόν] bitter wood, aethiopica refers to the origin of the tree (though most of it grows in Ghana). Hwentea fruits; look rather like small, twisted bean pods. They are dark brown, cylindrical, 2.5 to 5 cm long, and 4 to 6 mm thick; the contours of the seeds are visible from the outside. Each pod contains 5 to 8 kidney-shaped seed grains of approximately 5 mm in length. The hull is aromatic, but not the grain itself. Hwentea belongs to the family Annonaceae (custard apple family).  Hwentea is often smoked during the drying process which results in an attractive smoky–spicy flavor.

Other names

Apart from being called hwentea in Ghana, names such as Negro Pepper, Grains of Selim, African grains of Selim, Moor pepper, Kani pepper, Senegal pepper, African Black Pepper, Ethiopian Pepper, etc are attached to  Xylopia aethiopica.

Nutritional Content

Ekong and Ogan (1968), became the first researchers to report on the chemical composition of Xylopia aethiopica. Several diterpenes from the bark, fruits, and pericarp of the plant have been reported.  Four studies (Faulkner et al. 1985; Rabunmi and Pieeru, 1992; Harrigan et al. 1994, Ekundayo 1989) published a review of the volatiles in several Annonaceae species among which includes Xylopia aethiopica , and, reported that they consist mainly of mono and sesquiterpenoids with typical constituents being a- and b-pinene, myrcene, p-cymene, limonene, linalool, and 1,8-cineole. Lately, two new sesquiterpenes, elemol and guaiol (among other terpenes) were found in the essential oil of the fruit from the Republic of Benin (Ayedoun et al. 1996) while Jirovetz et al. (1997) gave a semblance of the aroma note from the essential oil in the fruit of Xylopia aethiopica from Cameroon.

Fast forward, another study by Tairu et al.(1999) reported that hwentea essential oil has been found to contain(2 to 4.5%) β-pinene, 1,8-cineol, α-terpineol, terpinene-4-ol, paradol, bisabolene, and other terpenes. Another study found, that linalool (E)-β-ocimene, α-farnesene, β-pinene, α-pinene, myrtenol, and β-phellandrene. Others such as traces of vanillin and 3-ethylphenol were also found.

Among the non-volatile constituents, tetracyclic diterpenes of the kaurane type have been identified; the kaurane structures are based on a tetracyclo[11.2.1.0.0]hexadecane skeleton. Kauranes and the structurally similar kolavanes and trachylobanes also appear in the bark. (Phytochemistry, 21, 1365, 1982), (Phytochemistry, 36, 109, 1994)

The essential oils of the stem bark (0.85%) and the leaves (0.5%) of X. aromatica have also been investigated. The bark oil consists mainly of α-pinene, trans-pinocarveol, verbenone, and myrtenol and differs remarkably from the leaf oil (spathulenol, cryptone, β-caryophyllene, and limonene) (Planta medica, 60, 282, 1994

Hwentea, Science

Antioxidant

Two recent studies by (Macedo et al. 2020; Osafo et al. 2018) found that hwentea is anti-inflammatory and hence can interfere with conventional inflammatory targets.  Additional two animals and one in vitrol studies (Nwozo et al. 2011; Mohammed and Islam, 2017; Moukette et al. 2015)  also found that hwentea is loaded with antioxidants. Another study by Babarinde and Adegoke( 2015) also found that tomatoes infused with hwentea at 4 & 5 % levels significantly retained the qualities evaluated.

Arthritis, Pain

One animal study by Obiri et al.(2014) evaluates the anti-arthritic effects of a 70% aqueous ethanol extract of the fruit of Xylopia aethiopica in a chronic inflammatory model.  Extract of 100, 300 and 600 mg /kg was used. The study found that hwentea suppresses joint inflammation and destruction in arthritic rats.  Another study by Ameyaw et al.(2014) also found that hwentea  can be used in the management of pain disorders including headache and neuralgia.  Two studies (Woode et al. 2012; Woode et al. 2016) on animals’ findings establish the analgesic properties of the ethanol fruit extract of hwentea in musculoskeletal pain.

Glaucoma, Eye Health

One important clinical trial by Igweet al. (2003) conducted on visually impaired volunteers found that hwentea is a safer spice that can be exploited in the management of exophoria and raised intraocular pressure (glaucoma) in instances where the efficacy of the older conventional drugs is insufficient. Exophoria is an eye condition that affects binocular vision and eye alignment. A person with exophoria will experience one of their eyes drifting outward, and their eyes will have difficulty working together. This study was conducted on humans, hence, it is good news for glaucoma or those with eye problems.

Blood sugar, cholesterol

Two studies (Mohammedet al. 2016; Mohammed and Islam, 2017) examined the anti-diabetic effects of hwentea in rats and found that hwentea is effective in lowering blood sugar and other metabolic diseases.

Another animal study by Nwozo et al.(2011) also found that hwentea is effective in lowering blood sugar and cholesterol. How hwentea can lower blood sugar is what we do not know. However, one study by Mohammed et al.(2021) found that a compound in hwentea called oleanolic acid is responsible for the antidiabetic action of hwentea fruit.

Antimicrobial, Antibacterial

One animal study by Tamfu et al.(2020) shows that hwentea can be used to manage food-borne infections. Another previous study by Fleischer et al.(2008) also found no effect that hwentea is effective against bacteria.

Cancer treatment

One study by Bakarnga-Via et al.(2014) investigated the antineoplastic activity of essential oils from fruits of these plants growing in Chad and Cameroon. Antineoplastic drugs are medications used to treat cancer. Other names for antineoplastic drugs are anticancer, chemotherapy, chemo, cytotoxic, or hazardous drugs. These drugs come in many forms, including liquids or pills. The researchers investigated the ability of hwentea essential oils on breast cancer and found that essential oils from fruits of hwentea have shown acceptable antineoplastic potency, and might be investigated further in this regard.

Another previous study by  Choumessi et al.(2012) aims to characterize the effects of extracts of this plant on cancer cells and found its potency. A recent study by Ribeiro et al.(2021) also found that hwentea is often referred to as an anticancer ingredient in Africa and this support their assertion. However, more studies are needed on humans.

Brain Support

One study by Adaramoye et al.(2010)  investigate the effects of hwentea fruit extract on oxidative stress in the brains of rats and found that it is beneficial. Another study by Biney et al.( 2016) also found that hwentea has antidepressant potential.

Liver Health                                        

One study by Iwuanyanwu et al.(2010) examined the effect of hwentea on liver health and found that it may be protective against liver damage in rats.

Warnings

Though Hwentea is safe. One experimental study on animals by Ehigiator and Adikwu(2020) showed that the use of hwentea may be detrimental to male reproduction function. The researchers used 200-800 mg/kg of hwentea extract daily for 15, 30, and 60 days. So moderation is key for men especially those seeking children.

Take Home

In conclusion, animal and in vitro studies have shown that hwentea supports the brain; blood sugar, and cholesterol management as well as blood pressure. An animal study also proved that it is an anticancer drug; liver support; glaucoma and eye support. It can treat schistosomiasis; arthritis and pain management. Finally, it is loaded with antioxidants.

NB:

Prof. Nyarkotey has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations to justify his write-ups.  My articles are for educational purposes and do not serve as Medical advice for Treatment. I aim to educate the public about evidence-based scientific Naturopathic Therapies.

The author is a Professor of Naturopathic Healthcare and President of Nyarkotey College of Holistic Medicine & Technology (NUCHMT)/African Naturopathic Foundation. E-mail: collegeofholisticmedicine@gmail.com.

References

1. Biney RP, Benneh CK, Ameyaw EO, Boakye-Gyasi E, Woode E. Xylopia aethiopica fruit extract exhibits antidepressant-like effect via interaction with serotonergic neurotransmission in mice. J Ethnopharmacol. 2016 May 26;184:49-57. doi: 10.1016/j.jep.2016.02.023. Epub 2016 Feb 20. PMID: 26902831.
2. Fleischer TC, Mensah ML, Mensah AY, Komlaga G, Gbedema SY, Skaltsa H. Antimicrobial activity of essential oils of Xylopia aethiopica. Afr J Tradit Complement Altern Med. 2008 Jun 18;5(4):391-3. doi: 10.4314/ajtcam.v5i4.31295. PMID: 20161962; PMCID: PMC2816578.
3. Ribeiro V, Ferreres F, Macedo T, Gil-Izquierdo Á, Oliveira AP, Gomes NGM, Araújo L, Pereira DM, Andrade PB, Valentão P. Activation of caspase-3 in gastric adenocarcinoma AGS cells by Xylopia aethiopica (Dunal) A. Rich. fruit and characterization of its phenolic fingerprint by HPLC-DAD-ESI(Ion Trap)-MSⁿ and UPLC-ESI-QTOF-MS². Food Res Int. 2021 Mar;141:110121. doi: 10.1016/j.foodres.2021.110121. Epub 2021 Jan 12. PMID: 33641988.
4. Adaramoye OA, Popoola BO, Farombi EO. Effects of Xylopia aethiopica (Annonaceae) fruit methanol extract on gamma-radiation-induced oxidative stress in brain of adult male Wistar rats. Acta Biol Hung. 2010 Sep;61(3):250-61. doi: 10.1556/ABiol.61.2010.3.2. PMID: 20724272.
5. Choumessi AT, Danel M, Chassaing S, Truchet I, Penlap VB, Pieme AC, Asonganyi T, Ducommun B, Valette A. Characterization of the antiproliferative activity of Xylopia aethiopica. Cell Div. 2012 Mar 12;7(1):8. doi: 10.1186/1747-1028-7-8. PMID: 22409878; PMCID: PMC3317441.
6. Moukette Moukette B, Pieme CA, Nya Biapa PC, Ngogang JY. In vitro antioxidant and anti-lipoperoxidative activities of bark extracts of Xylopia aethiopica against ion-mediated toxicity on liver homogenates. J Complement Integr Med. 2015 Sep;12(3):195-204. doi: 10.1515/jcim-2015-0002. PMID: 25941917.
7. Mohammed A, Victoria Awolola G, Ibrahim MA, Anthony Koorbanally N, Islam MS. Oleanolic acid as a potential antidiabetic component of Xylopia aethiopica (Dunal) A. Rich. (Annonaceae) fruit: bioassay guided isolation and molecular docking studies. Nat Prod Res. 2021 Mar;35(5):788-791. doi: 10.1080/14786419.2019.1596094. Epub 2019 Apr 16. PMID: 30990061.
8. Bakarnga-Via I, Hzounda JB, Fokou PV, Tchokouaha LR, Gary-Bobo M, Gallud A, Garcia M, Walbadet L, Secka Y, Dongmo PM, Boyom FF, Menut C. Composition and cytotoxic activity of essential oils from Xylopia aethiopica (Dunal) A. Rich, Xylopia parviflora (A. Rich) Benth.) and Monodora myristica (Gaertn) growing in Chad and Cameroon. BMC Complement Altern Med. 2014 Apr 4;14:125. doi: 10.1186/1472-6882-14-125. PMID: 24708588; PMCID: PMC4020318.
9. Tamfu AN, Ceylan O, Kucukaydin S, Ozturk M, Duru ME, Dinica RM. Antibiofilm and Enzyme Inhibitory Potentials of Two Annonaceous Food Spices, African Pepper (Xylopia aethiopica) and African Nutmeg (Monodora myristica). Foods. 2020 Nov 29;9(12):1768. doi: 10.3390/foods9121768. PMID: 33260317; PMCID: PMC7760624.
10. Ehigiator BE, Adikwu E. Toxicity study of ethanolic stem bark extract of Xylopia aethiopica on fertility indices of male rats: An experimental study. Int J Reprod Biomed. 2020 Apr 30;18(4):265-274. doi: 10.18502/ijrm.v13i4.6889. PMID: 32494765; PMCID: PMC7218670.
11. Woode E, Ameyaw EO, Boakye-Gyasi E, Abotsi WK, Oppong Kyekyeku J, Adosraku R, Biney RP. Effects of an ethanol extract and the diterpene, xylopic acid, of Xylopia aethiopica fruits in murine models of musculoskeletal pain. Pharm Biol. 2016 Dec;54(12):2978-2986. doi: 10.1080/13880209.2016.1199040. Epub 2016 Jul 18. PMID: 27430751.
12. Woode E, Ameyaw EO, Boakye-Gyasi E, Abotsi WK. Analgesic effects of an ethanol extract of the fruits of Xylopia aethiopica (Dunal) A. Rich (Annonaceae) and the major constituent, xylopic acid in murine models. J Pharm Bioallied Sci. 2012 Oct;4(4):291-301. doi: 10.4103/0975-7406.103251. PMID: 23248562; PMCID: PMC3523524.
13. Babarinde GO, Adegoke GO. Effect of Xylopia aethiopica aqueous extract on antioxidant properties of refrigerated Roma tomato variety packaged in low density polyethylene bags. J Food Sci Technol. 2015 Mar;52(3):1790-5. doi: 10.1007/s13197-013-1157-x. Epub 2013 Sep 21. PMID: 25745258; PMCID: PMC4348261.
14. Osafo N, Obiri DD, Antwi AO, Yeboah OK. The acute anti-inflammatory action of xylopic acid isolated from Xylopia aethiopica. J Basic Clin Physiol Pharmacol. 2018 Nov 27;29(6):659-669. doi: 10.1515/jbcpp-2018-0019. PMID: 30052517.
15. Mohammed A, Islam MS. Antioxidant potential of Xylopia aethiopica fruit acetone fraction in a type 2 diabetes model of rats. Biomed Pharmacother. 2017 Dec;96:30-36. doi: 10.1016/j.biopha.2017.09.116. Epub 2017 Nov 24. PMID: 28963948.
16. Nwozo SO, Orojobi BF, Adaramoye OA. Hypolipidemic and antioxidant potentials of Xylopia aethiopica seed extract in hypercholesterolemic rats. J Med Food. 2011 Jan-Feb;14(1-2):114-9. doi: 10.1089/jmf.2008.0168. PMID: 21244241.
17. Mohammed A, Koorbanally NA, Islam MS. Anti-diabetic effect of Xylopia aethiopica (Dunal) A. Rich. (Annonaceae) fruit acetone fraction in a type 2 diabetes model of rats. J Ethnopharmacol. 2016 Mar 2;180:131-9. doi: 10.1016/j.jep.2016.01.009. Epub 2016 Jan 12. PMID: 26795545.
18. Ameyaw EO, Woode E, Boakye-Gyasi E, Abotsi WK, Kyekyeku JO, Adosraku RK. Anti-allodynic and Anti-hyperalgesic effects of an ethanolic extract and xylopic acid from the fruits of Xylopia aethiopica in murine models of neuropathic pain. Pharmacognosy Res. 2014 Apr;6(2):172-9. doi: 10.4103/0974-8490.129041. PMID: 24761123; PMCID: PMC3996755.
19. Igwe SA, Afonne JC, Ghasi SI. Ocular dynamics of systemic aqueous extracts of Xylopia aethiopica (African guinea pepper) seeds on visually active volunteers. J Ethnopharmacol. 2003 Jun;86(2-3):139-42. doi: 10.1016/s0378-8741(02)00371-9. PMID: 12738077.
20. Ayedoun, A.M., B.S. Adeoti, and P.V. Sossou. 1996. Influence of fruit conservation methods on the essential oil composition of Xylopia aethiopica (Dunal) A. Richard from Benin. Flav. Fragr. J. 11:245
21. Ekundayo, O. 1989. A review of the volatiles of the Annonaceae. J. Essent. Oil Res. 1:223.
22. Ekong, D.E.U. and A.U. Ogan. 1968. Constituents of Xylopia aethiopica. Structure of xylopic acid, a diterpene acid. J. Chem. Soc. C, 1968, 311.
23. Faulkner, D.F., D. Lebby, and P.G. Waterman. 1985. Chemical studies in the Annonaceae. Part 19. Further diterpenes from the stem bark of Xylopia aethiopica. Planta Med. 51:354.
24. Harrigan, G.G, V.S. Bolzani, A.A.L. Gunatilaka, and D.I.G. Kingston. 1994. Kaurane and trachylobane diterpenes from Xylopia aethiopica. Phytochemistry 36:109.
25. Jirovetz, L., G. Buchbauer, and M. Ngassoum. 1997. Investigation of the essential oils from the dried fruits of Xylopia aethiopica (West African "Peppertree") and Xylopia parviflora from Cameroun. Ernährung 21:1.
26. Rabunmi, R. and E. Pieeru. 1992. Japanese patent JP 92-173277. Chem. Abstr., 120:270896.
27. Tairu, A.O., T. Hofmann, and P. Schieberle. 1999. Identification of the key aroma compounds in dried fruits of Xylopia aethiopica. p. 474–478. In: J. Janick (ed.), Perspectives on new crops and new uses. ASHS Press, Alexandria, VA.
28. Macedo T, Ribeiro V, Oliveira AP, Pereira DM, Fernandes F, Gomes NGM, Araújo L, Valentão P, Andrade PB. Anti-inflammatory properties of Xylopia aethiopica leaves: Interference with pro-inflammatory cytokines in THP-1-derived macrophages and flavonoid profiling. J Ethnopharmacol. 2020 Feb 10;248:112312. doi: 10.1016/j.jep.2019.112312. Epub 2019 Oct 16. PMID: 31629028.
29. Obiri DD, Osafo N, Ayande PG, Antwi AO. Xylopia aethiopica (Annonaceae) fruit extract suppresses Freund's adjuvant-induced arthritis in Sprague-Dawley rats. J Ethnopharmacol. 2014 Mar 28;152(3):522-31. doi: 10.1016/j.jep.2014.01.035. Epub 2014 Feb 6. PMID: 24509151.