Roland MARINI DJANG'EING'A

Prof. Roland MARINI DJANG'EING'A


Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 August 2021 in The American Journal of Tropical Medicine and Hygiene
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Journal Article
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CTChristelle Ange Waffo Tchounga
Christelle Ange Waffo Tchounga
PSPierre-Yves Sacré
Pierre-Yves Sacré
PHPatient Ciza Hamuli
Patient Ciza Hamuli
RMRose Ngono Mballa
Rose Ngono Mballa
ENEmmanuel Nnanga Nga
Emmanuel Nnanga Nga
RDRoland MARINI DJANG'EING'A
Roland MARINI DJANG'EING'A
: Poor-quality medicines are the cause of many public health and socioeconomic problems. We conducted a review to acquire an overview of the situation concerning such medicines in Cameroon. Different searches were performed on databases from several websites of the WHO, the Ministry of Public Health of Cameroon, the Anti-Counterfeit Medicine Research Institute, the Global Pharma Health Fund, and the Infectious Disease Data Observatory. We identified 92 publications comprised of 19 peer-reviewed studies and 73 alerts. Based on studies completed, 1,664 samples were analyzed, and the prevalence of substandard and falsified (SF) medicines could be estimated for 1,440 samples. A total of 67.5% of these samples were collected from the informal sector, 20.9% from the formal sector, and 11.6% from both sectors. We found a prevalence of SF medicines across the peer-reviewed studies of 26.9%, whereas most of the SF medicines belonged to the anti-infective class. The problem of SF medicines is not studied sufficiently in Cameroon; therefore, efforts should be made to conduct adequate studies in terms of representativity and methodology.

1 February 2023 in The American Journal of Tropical Medicine and Hygiene
Verified
Journal Article
Closed access
PDF file
CTChristelle Ange Waffo Tchounga
Christelle Ange Waffo Tchounga
PSPierre-Yves Sacré
Pierre-Yves Sacré
PHPatient Ciza Hamuli
Patient Ciza Hamuli
RMRose Ngono Mballa
Rose Ngono Mballa
CBCharlotte De Bleye
Charlotte De Bleye
RDRoland MARINI DJANG'EING'A
Roland MARINI DJANG'EING'A
: Quality is one of the essential components of medicines and needs to be ensured to preserve the population’s health. This can be achieved through post-marketing quality control of medicines and is one of the most important duties of national regulatory authorities. In collaboration with the Cameroonian National Drug Quality Control and Valuation Laboratory, the decision was made to initiate a prevalence study to assess the quality of antiinfective medicines in Cameroon. A total of 150 samples of ciprofloxacin tablets and 142 samples of metronidazole tablets were collected from 76 licensed pharmacies and 75 informal vendors in three cities in Cameroon using a random strategy wherever possible and a mystery shopper approach. Three tests were carried out on each of the samples. Visual inspection allowed to find two falsified samples (0.7%) due to lack of information about the manufacturing company, and five more samples (1.7%) were deemed to be substandard due to flaws in the product. An additional 13 samples (4.5%) failed disintegration testing, and six (2.1%) others failed high-performance liquid chromatography assay testing due to insufficient active pharmaceutical ingredient (API) content. All samples were found to contain some API. A prevalence of 7.9% substandard or falsified (SF) medicines was found. Moreover, the prevalence of outlets selling SF medicines was greater in the informal sector (26.7%) than in the formal sector (2.6%). Although the prevalence of SF medicines found was low, efforts need to be made by national regulatory authorities to monitor the pharmaceutical market more closely.

2 August 2023 in The American Journal of Tropical Medicine and Hygiene
Verified
Journal Article
Closed access
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PTPierrot Mwamba Tshilumba
Pierrot Mwamba Tshilumba
AIAnge Booka Ilangala
Ange Booka Ilangala
JKJeremie Mbinze Kindenge
Jeremie Mbinze Kindenge
IKIsaac Mutshitshi Kasongo
Isaac Mutshitshi Kasongo
GKGuelord Kikunda
Guelord Kikunda
JNJean-Baptiste Kalonji Ndoumba
Jean-Baptiste Kalonji Ndoumba
: The access to afford safe, effective, and genuine medications is a major challenge for people in low- to middle-income countries. This study aimed at developing and validating simple, accurate, and inexpensive analytical liquid chromatography and ultraviolet-visible spectrophotometric methods to ensure quality control of antibiotics sold in formal and informal pharmaceutical markets. It focused on four antibiotics (azithromycin [AZT], cefadroxil [CFD], cefixime [CFX], and erythromycin [ERH]) used to treat infectious diseases in the region of Haut-Katanga in the Democratic Republic of the Congo (DRC). The total error strategy (accuracy profile) matching with the validation requirements of International Council on Harmonization was used for the validation. The validation results showed that three analytical methods of AZT, CFD, and ERH were validated according to the accuracy profile obtained, whereas the proposed method of CFX was not validated. Therefore, the United State Pharmacopoeia method permitted to quantify CFX samples. The dosage intervals ranged from 25 to 75 µg/mL for CFD, from 750 to 1,500 µg/mL for AZT, and from 500 to 750 µg/mL for ERH. The application of the validated method to samples collected (N = 95) allowed the detection of 25% substandard antibiotics with a rate of poor quality much higher in the informal circuit compared with the formal one (54% versus 11%; P < 0.05). The routine application of these methods will strengthen the quality control of drugs marketed in DRC. This study gives evidence for the availability of poor-quality antibiotics in the country, requiring the immediate attention of the national medicine regulatory authority.

15 April 2025 in Molecules
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BMBORIVE Amani Marguerite
BORIVE Amani Marguerite
Michel FREDERICHMichel FREDERICH
Michel FREDERICH
OJOlivia Jansen
Olivia Jansen
OBOlivier Bonnet
Olivier Bonnet
ALAllison Ledoux
Allison Ledoux
RDRoland MARINI DJANG'EING'A
Roland MARINI DJANG'EING'A
Sickle cell disease (SCD) is a neglected tropical disease (NTD) associated with severe health consequences, including death. Hibiscus tiliaceus L., from the Malvaceae family, is used traditionally in Kisangani, Democratic Republic of the Congo (DRC), to alleviate symptoms of SCD. However, the specific phytochemicals responsible for the observed therapeutic effects remain unclear. This study aims to characterize the aqueous leaf extract of H. tiliaceus and assess its biological activity against sickle cell disease, including its antisickling, antioxidant, and anti-inflammatory effects. Using techniques such as TLC, HPLC-UV/DAD, LC-MS, and NMR, we identified kaempferol 3-O-rutinoside and rutin in the aqueous extract of H. tiliaceus leaves. Rutin exhibited potent antioxidant and anti-inflammatory activities, with IC50 values of 5 µg/mL and 2.5 µg/mL, respectively. Conversely, kaempferol 3-O-rutinoside demonstrated superior antisickling activity, normalizing sickled red blood cells with an IC50 < 12.5 µg/mL. Due to the pathophysiology of SCD, which involves the polymerization of red blood cells, which induces oxidative stress and an inflammatory response, this study suggests the importance of H. tiliaceus for the management of SCD. Additionally, the combined effect of molecules in H. tiliaceus will help in normalizing erythrocytes, inhibiting free radicals generated by early hemolysis, thus contributing to inflammatory processes reduction. This finding provides evidence and validates the traditional use of H. tiliaceus aqueous extract for the management of SCD.

1 July 2020 in International Health
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Journal Article
Open access
DLDon Jethro Mavungu Landu
Don Jethro Mavungu Landu
MFMichel Frédérich
Michel Frédérich
JKJoseph Manzambi Kuwekita
Joseph Manzambi Kuwekita
CNChristian Bongo-Pasi Nswe
Christian Bongo-Pasi Nswe
JMJ K Mbinze
J K Mbinze
RDRoland MARINI DJANG'EING'A
Roland MARINI DJANG'EING'A
Background: In the context of old pharmaceutical legislation and regulations not adapted to current realities, the aim of the present studywas to evaluate the existing pharmaceutical system in peri-urban areas of Kinshasa. Methods: A prospective study was carried out during the period 2016-2018. The most used antimalarial medicines were identified through household and pharmaceutical establishment surveys. The samples of the obtained medicines were assayed with generic separation methods using the high-performance liquid chromatography technique coupled to a diode array detector. The registration status was checked for 126 antimalarial brand names. A characterization was carried out in 196 pharmaceutical establishments on the basis of standards set out by the Ministry of Health. Results: Of the 75 samples assayed, 19% (14/75) were non-compliant. Of the 124 brand names, 46.0% (57/124) were unlicensed and 14.5% (18/124) had an expired licence. Of the 196 pharmaceutical establishments, only 2 (1.0%) had an authorization to practice, none met all the Ministry of Health minimum standards and 24.5% (48/196) met the World Health Organization Guidelines for the Storage of Essential Medicines and Other Health Commodities. Conclusions: More resources should be mobilized to apply regulator sanctions.

18 March 2025 in Molecules
Verified
Journal Article
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WGWendinmi Bertrand Florent GOUMBRI
Wendinmi Bertrand Florent GOUMBRI
OJOlivia Jansen
Olivia Jansen
RDRoland MARINI DJANG'EING'A
Roland MARINI DJANG'EING'A
Michel FREDERICHMichel FREDERICH
Michel FREDERICH
RSRASMANE SEMDE
RASMANE SEMDE
AMAnge Mouithys-Mickalad
Ange Mouithys-Mickalad
Shea butter (SB) is a raw material fat obtained from Vitellaria paradoxa C.F. Gaertn kernels. We investigated the direct and indirect protective effects of 10 traditional and industrial SBs and their polar extracts on cell-free systems using ABTS and DPPH radical scavenging assays as well as on singlet oxygen (1O2) produced by Rose Bengal (RB) photosensitization. Their effects against RB-induced HaCaT cell phototoxicity were also explored. A spectrophotometric assay and HPLC were performed to quantify and identify phenolic content, which was between 14.16 and 82.99 ppm pyrogallol equivalent. These variations could be due to the SB origin and extraction process. These polar fractions exhibited moderate DPPH and strong ABTS radical-scavenging activity. By applying the UV–visible technique, we demonstrated that SBs and their phenolic compounds behave as 1O2 quenchers in a dose-dependent manner. Moreover, using a UVR-like model after the irradiation of RB, both polar extracts and crude SB exhibited photoprotective effects, highlighting the indirect protective action. In acellular and cellular models, SB and its polar extracts can act as a free radical scavenger against reactive oxygen species and 1O2 quenchers. Due to the maximum absorbance of SB at 280 nm and the antioxidant effect of 1O2 quenching, SB polar extracts exhibit photoprotective properties.