Proximate Composition, Phytochemical and Antimicrobial Activity of Aqueous and Ethanolic Extracts of Hunteria umbellata on some Clinical Isolates

A medicinal plant is any plant which has therapeutic used and are used for drug production. The use of medicinal plants for traditional uses is well known in rural areas and many developing countries. This study was undertaken to evaluate the antibiotic and therapeutic importance of the extracts of Hunteria umbellata against selected clinical isolates known to cause diseases to man. Agar well diffusion method was used to determine the antibacterial activity of Hunteria umbellata. The proximate composition showed that carbohydrate with 71.55±0.10 % had the highest value. The elemental composition analyzed showed that Fe had the highest amount. The phytochemical screening of both aqueous and ethanolic extracts showed the presence of oxalate, phytate, tannins, flavonoids, saponins, alkaloids, phenols, cyanogenic glycoside and anthraquinones. The clinical isolates E. coli, S. pneumonia, S. pyogenes, S. aureus, Staphylococcus sp., P. aeruginosa, Micrococcus sp., Klebsiella sp., Proteus sp., Bacillus sp., S. epidermidis, Candida albicans, S. cerevisiae. The zone of inhibition of aqueous and ethanolic extracts in comparison with the conventional antibiotics showed that the extracts had better antibacterial properties. The results obtained showed the important use of H. umbellata in ethnomedicine. DOI: https://dx.doi.org/10.4314/jasem.v26i1.5 Open Access Article: (https://pkp.sfu.ca/ojs/) This an open access article distributed under the Creative Commons Attribution License (CCL), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Impact factor: http://sjifactor.com/passport.php?id=21082 Google Analytics: https://www.ajol.info/stats/bdf07303d34706088ffffbc8a92c9c1491b12470 Copyright: Copyright © 2022 Udinyime and Agbedo Dates: Received: 23 August 2021; Revised: 21 December 2021; Accepted: 06 January 2022

A medicinal plant is any plant which has therapeutic uses and are used for the production of antimicrobial drugs (Bouayed et al., 2008), antioxidant, antiinfections and anti-tumor activities (Akroum et al., 2009). Plants are the source of medicine for many people in different countries, which make diseases to be treated with herbal medicines gotten from various plants. This present day pharmaceutical companies depend on the diversity of secondary metabolites in plants of which at least 12,000 have been isolated and this can be estimated to be up to 10 % of the total of the secondary metabolites (Mallikharjuna et al., 2007). The medicinal value of plants lies in some chemical substances that produce a definite physiological action on the human body. The most important of these bioactive compounds of plants are alkaloids, flavonoids, tannins and phenolic compounds (Edeoga et al., 2005). Hunteria umbellate K. Schum (Apocynaceae) is a tree with evergreen crown of about 15 m -22 m in height (Oliver, 1986). It is located in the tropical zone of the southern part of Nigeria where it is called local names such as osu (Edo), abeere (Yoruba) and nkpokiri (Igbe et al., 2009). The leaves are broad, abruptly acuminate and broadly lineate The fruit is about 5 cm -25 cm and consist of globose mericaps of 3 cm -6 cm long (Keay et al., 1964). The genus Hunteria has been used severally for different herbal medicine. Different kinds of medicine gotten from the extracts of different parts of the plant are presently being used in the treatment of various clinical diseases, although there is little knowledge on their mechanisms of action (Igbe et al., 2010). Therefore, the objective of this paper is to evaluate the proximate composition, phytochemical and antimicrobial activity of aqueous and ethanolic extracts of Hunteria umbellata on some clinical isolates.

MATERIALS AND METHODS
Sample collection and identification: The plant seed of H. umbellata were purchased from a market in Oshodin Local Government Area, Lagos State. The plant seeds were dried for three weeks, thereafter the epicarps were removed and further dried for another three (3) weeks. The air drying was done to protect the bioactive components of the plant seeds. The preliminary identification of the plant was carried out by Dr. E. I. Aigbokhan, Department of Plant Biology and Biotechnology, University of Benin, Benin City.
Preparation of sample: The dried seeds of H. umbellata were pulverized using electronic milling machine grinder, Lab. Mill, Serial No. 4745, Christy and Norris Ltd, England. The pulverized seeds were stored in air tight plastic container for further experimentation.
Extraction of plant materials: The extraction was carried out according to the methods of Igbe et al. (2009). Four hundred grammes (400 g) of the powdered form were macerated in a sterile grinder and transferred into Pyrex flasks containing 1.5 litre of aqueous (sterile distilled water) and non-aqueous solvent (ethanol) respectively, the suspension was allowed to stay for 24 hrs for the aqueous and 72 hrs for the non-aqueous mixture. At the end of extraction, the homogenate was filtered with a Whatman Filter Paper No. 1 using a glass funnel. The filtrates were labelled accordingly for subsequent use and concentrated using water-bath at 80 0 C to dryness. The dried extract of both solvents were preserved in clean glass containers at 4 0 C for further experimentation.
Proximate and Mineral elemental composition: The proximate and mineral elemental analyses were carried out according to the methods of AOAC (1999).

Determination of the quantitative phytochemical components of the pulverised seeds of H. umbellate:
The quantitative phytochemical analyses of the powdered seeds of H. umbellata were determined according to the methods of Harborne (1973 The test isolates were transported to the laboratory in an ice pack box for experimentation.  Table 2 showed the mineral elemental composition of the seeds of H. umbellata which showed the presence of these elements K, Na, P, Mg, Ca, Fe, Mn, Zn and Cu. Table 3 revealed the presence of phytochemicals such as oxalate, phytate, tannins, flavonoids, saponins, alkaloids, phenols, cyanogenic glycoside and anthraquinones. Alkaloids had the highest percentage for both aqueous and ethanolic extracts. The results of the diameter of the zones of inhibition in Table 4 Table 1 showed that carbohydrate was the highest among the other proximate parameters which is in agreement with the research carried out by Morakinyo et al. (2020). Nutritional and proximate analysis of plants are used to evaluate their nutritional importance as they are being employed by humans for medicinal purposes (Hussain et al., 2009). Carbohydrate content of 72.11±0.80 Hunteria umbellata was reported by Morakinyo et al. (2020) which supports the result of 71.55±0.10 of carbohydrate content of Hunteria umbellata in this study. The result of elemental analyses shows the presence of K, Na, P, Mg, Ca, Fe, Mn, Zn, Cu ( Table 2). The presence of these elements in the seeds of H. umbellata is an indicator of its nutritional quality. The result of the nutritional composition of Hunteria umbellata in this research is in agreement with the result of Morakinyo et al. (2020) which showed the presence of minerals such as calcium, phosphorus, zinc and sodium. The presence of these elements in the seeds of H. umbellata makes it useful in the prevention and control of diseases, acid-base balance, regulation of osmotic pressure, conduction of nerve impulse, muscle contraction (particularly the cardiac muscle), bones and teeth regulation, cell membrane function (Murray et al., 2000). The results in Table 4 revealed the presence of the phytochemical components such as oxalate, phytate, tannins, flavonoids, saponins, alkaloids, phenols cyanogenic glycoside and anthraquinones. Saponins, alkaloids and phenols were found to be present in high concentrations, which supports the findings of Adeneye and Adeyemi (2009); Morakinyo et al. (2020) on the research done on the seeds of H. umbellata, and they reported the presence of tannis, alkaloids, cardiac glycosides, flavonoids, saponins, anthraquinone and reducing sugar with alkaloids present in high concentration. The extraction of bioactive components from H. umbellata had led to the discovery of potent compounds with low toxicity. The phytochemicals contained in H. umbellata in this study has been shown severally to be active against several infections (Owolabi et al., 2007). A compound such as alkaloids present in Table  4 is known to be an antimalaria agent, analgesics and can act as stimulants. Glycoside moieties such cyanogenic glycosides, saponins and anthraquinones have been reported to be able to inhibit tumor growth, antiparasitic agents, antidepressant (Ajayi and Ojelere, 2013). Phytochemicals are known to accumulate in different parts of the plant such as in the leaves, flowers, stems, roots, fruits or seeds (Costa et al., 1999). Phenol also reported in the present study also plays significant role in the managements of antiaging, antiapoptosis, anticarcinogen, antiinflammation, antiatherosclerosis, cardiovascular protection and improvement of endothelial function (Han et al., 2007). Glycosides which are present in Table 4 have been reported to lower blood pressure (Nyarko and Addy, 1990). The results of phytochemicals therefore report the increasingly valuable reservoir of bioactive compounds of substantial medicinal merit. The results in Tables 4, 5  The concentrations of the minimum inhibitory concentration and minimum bacteriocidal concentration as shown in Tables 4, 5 and 7 were observed to be very effective against the clinical isolates even at low concentrations. This further proves the antibacterial efficacy of the aqueous and ethanolic extracts of H. umbellata.   Pavendan and Sebastine (2012) where it was reported that the leaf extract of a medicinal plant E. singampattiana was effective against C. albicans.

RESULTS AND DISCUSSION
The result of this study is in agreement with the research carried out by Selvamohan et al. (2012) where the aqueous extracts of three medicinal plants P. niruri, P. emblica and P. vera showed inhibitory activity against selected human pathogenic microbes such as Klebsiella sp., P. aeruginosa, E. coli and S. aureus which were also used in this study. This research is also in agreement with the research carried out by Adegoke et al. (2010) where the ethanolic extract of Phyllanthus amarus showed inhibitory effect on S. aureus, P. aeruginosa, Klebsiella sp., and E. coli. It was observed in this research work that increase in the concentration of the ethanolic extract increased susceptibility of the test isolates.

UDINYIWE, CO; AGHEDO, ES
This confirms the research of Obi and Onuoha (2000) where it was reported that the increase in inhibitory effects as the concentrations of the extract increased may be as a result of the ethanol ability in extracting most of the active ingredients of the plants. However, the ability of the extracts to inhibit the growth of Staphylococcus aureus, Pseudomonas sp., Klebsiella sp. and Escherichia coli indicated that these organisms do not possess the ability of inactivating the active ingredients in the extracts or other mechanisms which include exclusion of the substance from the cell and modification of the target site of the substance.
The antimicrobial activities of the extracts possess antibacterial activity against all the test isolates. In this research ethanol extract showed more activity against the bacterial isolates than the aqueous extract. This may be due to the higher volatility of the ethanol which tends to extract more active compounds from the seeds of H. umbellata than aqueous (Ibekwe et al., 2001). The results in Table 4, 5 and 7 reveals that the antimicrobial activity of aqueous and ethanolic extract of H. umbellata can be compared and said to be better than the activity of the conventional drugs on the test isolates. The result in Table 6 showed the poor performance of the conventional antibiotics on the test isolates. This result showed that the aqueous and ethanolic extracts of H. umbellata can be used in the formulation of antibiotic drugs which will have strong inhibitory effect on clinical isolates that have been known to cause diseases. The presence of the phytochemicals in the seeds of H. umbellata have been known to cause curative activity against several bacteria and it is not surprising that this plant extracts are used traditionally by herbalist to cure bacteria related ill-health (Dahiru et al., 2006). The findings of Muanya (2008) which is in agreement with the result of this study reported that Garcinia kola a medicinal plant has strong antibiotic activities and are very effective against disease-causing microorganisms such as E. coli, S. aureus, P. aeruginosa, Salmonella sp., Streptococcus sp., Candida albicans, Vibrio cholera and Neisseria gonorrhoea. This study has further authenticated the antimicrobial potential of H. umbellata and justifies its use in the daily diet to treat mankind from certain ailments.

Conclusion:
The results of this study showed that H. umbellata seeds has medicinal properties which helps in the sustenance of health of individuals in communities. The presence of phytochemicals in this plant seeds plays a lot of roles in its therapeutic effects.
Medicinal plants have been used as healing agents in many parts of the world especially Africa where access to formal health care is limited.