After the World Health Organization lifted the public health emergency of international concern for COVID-19, statistics indicate that approximately 689 million people tested positive for COVID-19, with approximately 7 million fatalities attributed to the disease (https://www.worldometers.info/coronavirus/). Various therapeutic approaches were explored in the management of COVID-19, including antibiotics (azithromycin), antiparasitic agents (hydroxychloroquine), antiviral medications (remdesivir), monoclonal antibodies (casirivimab), steroids (dexamethasone), and immune modulators (tocilizumab), anticoagulants, as well as oxygen therapy and other supportive measures for patients experiencing respiratory distress (Mehraeen et al., 2022; Murakami et al., 2023; Panahi et al., 2023). Other approaches such as the search for new treatments using traditional remedies were also explored, as well as vaccines (Rahman et al., 2022; Soheili et al., 2023).

Gabon, with a population of approximately 2.3 million, has grappled with COVID-19, with statistics revealing approximately 49,000 individuals testing positive and resulting in 307 recorded fatalities since the first reported case in 2020 (https://www.worldometers.info/coronavirus/country/gabon/). The diagnostic of the disease was carried out by Laboratoire Professeur Daniel Gahouma. The latter was the specialized state-of-the-art technology specifically established to address the challenges posed by the pandemic. In addition, COVID-19 treatment protocols in Gabon have involved antibiotherapy in combination with vitamins, paracetamol, zinc, and vaccine.

However, despite the availability of medications and vaccines, and due to fears regarding potential adverse effects associated with vaccination, the Gabonese population has turned to medicinal plants for the prophylaxis and treatment of symptoms associated with this viral disease, similar to the populations of several other countries including Algeria, Brazil, Colombia, Cameroon, Morocco, and Peru (Belmouhoub et al., 2021; Villena-Tejada et al., 2021; Chebaibi et al., 2022; Cordoba-Tovar et al., 2022; Mvogo Ottou et al., 2022; da Silva et al., 2023). Most Gabonese people often rely on medicinal plants due to their long tradition of plant-based medicine. The Gabonese population strongly believes in the efficacy of medicinal plants, considering them crucial in managing COVID-19, particularly due to symptoms resembling those of malaria and flu. Indeed, several symptoms such as respiratory disorders, colds, coughs, fever, and joint pain commonly associated with flu and malaria are typically treated using plant-based remedies by the population. Ancestral knowledge passed down from generation to generation may contain treasures of effective natural remedies against this virus. Therefore, the present study aimed to document and valorize plants used by the Gabonese population to prevent or cure COVID-19 and to identify specific plant species deserving further investigation as potential treatments against coronavirus infections.

The present study aimed to highlight the plants used in Gabon to prevent and/or treat symptoms associated with COVID-19. Survey participants included individuals from the general population, traditional healers, and medicinal plant vendors. The findings revealed that most of the participants were male subjects, with the predominant age group being 31–44 years. These results suggest that men displayed a greater interest in the survey compared to women, likely due to the prevalence of male traditional healers and medicinal plant vendors. The age group of 31–44 years was particularly noteworthy as it represents the demographic most inclined to embrace traditional medicine and seek to reclaim traditional knowledge. In addition, a large number of informants had a university education. The high level of education among the majority of respondents indicates that, despite heightened awareness of the ongoing pandemic, the population continues to associate medicinal plants with the prevention and treatment of diseases exhibiting flu-like symptoms. Khadka et al. (2021) supported this finding, reporting that educated people had a preference for modern medicine, but during COVID-19, they used medicinal plants as an alternative medicine option. Gabon is very rich in plant biodiversity, and the knowledge of medicinal plants used to treat infections or conditions such as malaria or influenza is deeply rooted within the population, is transmitted from generation to generation, and is often shared by traditional healers with individuals seeking information. Consequently, when the pandemic emerged, the Gabonese population likened it to a blend of malaria and flu due to the overlapping symptoms with COVID-19, including fever, joint and body ache, fatigue, coughing, and cold symptoms. Subsequently, people began treating these symptoms using plants commonly used to treat influenza and malaria. The study findings indicate that these specific symptoms were the most frequently treated by the population. Surveys conducted in different countries such as Bangladesh and South Africa also described these symptoms as the most commonly treated in their respective countries (Phumthum et al., 2021; Rafiqul Islam et al., 2021; Zondi and Ehaine, 2022). The remedies predominantly involved the use of barks and leaves, prepared through infusion, decoction, or maceration. Notably, steam baths emerged as the second most common mode of administration, a method traditionally employed in Gabon specifically for treating malaria. Other studies also mentioned steam baths or steam inhalation as modes of administration, arguing that this method has been used for decades as a home remedy for cold and pain (Rafiqul Islam et al., 2021; Mvogo Ottou et al., 2022; Zondi and Ehaine, 2022). The study also revealed that the majority of respondents had contracted COVID-19 and that only 3% of them did not take treatment based on medicinal plants. Among the remaining respondents who claimed to have never developed any symptoms, medicinal plants were used for prevention. These results suggest that medicinal plants may have provided protection against coronavirus infection for individuals who used them. Further research, including clinical trials, is necessary to confirm these findings and to determine the safety and efficacy of the plants. In a similar context, results from a study carried out in Peru on the use of medicinal plants for COVID-19 prevention and respiratory symptom treatment showed that most of their respondents did use plants for these purposes (Villena-Tejada et al., 2021).

Ethnobotanical surveys often employ various indexes to unveil or highlight medicinal plants that are most frequently used or deemed most beneficial for the treatment of a specific disease. These indexes help quantify and analyze the importance of different plant species within a particular cultural or ecological context. In the present study, the results indicated that several indexes, including RFC, UV, or RI, collectively highlighted the plants most frequently used for the prevention or treatment of COVID-19. Notably, Annickia chlorantha, Allium sp., Citrus sp., Alstonia congensis, Zingiber officinale, Carica papaya, Staudtia kamerunensis, Mangifera indica, Combretum micranthum, Cymbopogon citratus, Newbouldia laevis, Ocimum gratissimum, Gymnanthemum amygdalinum, Musa x paradisiaca, and Artemisia annua emerged as the most commonly cited. Surveys conducted worldwide documented the use of several of these plants in the prevention and/or treatment of the disease, regardless of geographical location, climate diversity, or the variability of flora in the different regions. Hence, plants like Allium sp., Citrus sp., Zingiber officinale, Carica papaya, Mentha piperita, Cymbopogon citratus, and Ocimum sp. were used in diverse regions such as Cameroon, Morocco, Iraq, Thailand, Nepal, and Turkey (Akbulut, 2021; Khadka et al., 2021; Phumthum et al., 2021; Abdulrahman et al., 2022; Mvogo Ottou et al., 2022). ICF and POPUT are indispensable tools in ethnopharmacological surveys, offering valuable insights into the consensus, popularity, and cultural significance of medicinal plants within a community (Asiimwe et al., 2021; Anwar et al., 2023). Their application enhances the understanding of traditional healthcare practices and guides scientific research efforts. In this regard, symptoms such as fever, cough, and fatigue, which displayed high index values, appeared to be well-managed by the population, who are knowledgeable about several plants that can alleviate these symptoms. These plants merit further investigation based on the specific symptoms they are reported to alleviate.

The study findings suggest that plants traditionally used in the treatment of malaria are potential candidates for drug development against coronaviruses. Notably, the species prominently cited in this study have undergone assessment for their antiplasmodial activity, both in animal models and in vitro, demonstrating significant potential for managing malaria (Afolabi and Oyewole, 2020; Tajbakhsh et al., 2021; Indradi et al., 2023). These plants include Annickia chlorantha, Zingiber officinale, Alstonia congensis, Newbouldia laevis, Ocimum gratissimum, Gymnanthemum amygdalinum, Artemisia annua, and Carica papaya (Cimanga et al., 2019; Abubakar et al., 2020; Assogba, 2020; Wang et al., 2020; Kshirsagar and Rao, 2021; Tajbakhsh et al., 2021). Furthermore, the same plants demonstrate noteworthy anti-inflammatory and immunomodulatory effects, which are particularly valuable in addressing the cytokine storm induced by COVID-19 (Omoregie and Pal, 2016; Eftekhar et al., 2019; Abubakar et al., 2020; Olaoye et al., 2021; Kshirsagar and Rao, 2021; Mezui et al., 2022; Kamelnia et al., 2023; Nishitha et al., 2023; Ukwubile et al., 2023; Yuandani et al., 2023). In addition, plants such as Z. officinale, Artemisia annua, Carica papaya, Citrus sp., Allium sativum, and Cymbopogon citratus were assessed for their antiviral activity against SARS-CoV-2 (Belkessam et al., 2021; Haridas et al., 2021; Oladele et al., 2021; Thuy et al., 2021; Adel et al., 2022) (Table 4). Various studies, using molecular docking, cell-based assays, and clinical trials, were conducted to elucidate the mechanisms underlying the antiviral activity of the cited plants. Collectively, the findings of these studies suggest that all tested plants are potential putative inhibitors of the proliferation of SARS-CoV-2, ACE2 host receptor, and major protease. They impede the attachment, membrane fusion, and internalization of SARS-CoV-2 into host cells, as well as the viral replication and transcription processes. Furthermore, numerous trials currently investigate several promising and potent phyto-based formulations for the treatment of SARS-CoV-2 infections (Alam et al., 2021). These formulations include a range of bioactive metabolites, plant extracts, functional foods, and plant-based preparations. For example, hesperidin, which is present in some of the plants described in our study (Table 4), is involved as primary therapy in a phase II trial (Alam et al., 2021). In addition, a preliminary trial of the effect of Allium sativum in patients with SARS-CoV-2 showed an improvement in the general condition with the resolution of most of the symptoms (fever, headache, asthenia, ageusia, anosmia, and diarrhea) (Belkessam et al., 2021).

Analysis of the data highlighted that all the plants described in Table 4 showing promising activity against SARS-CoV-2 are listed in Table 3 as components of the popular recipes used in the prevention and/or treatment of COVID-19. A combination of these plants with antiviral and anti-inflammatory effects in a recipe strengthens the hypothesis that these recipes could effectively prevent or treat the coronavirus infection, thereby sustaining their use by the Gabonese population. So, taken together, the results of the present study showed the potential of medicinal plants as independent therapies, complementary or alternative medicines for the management of symptoms associated with COVID-19.

A concern could be raised regarding the potential overharvesting of certain species such as Annickia chlorantha, Allium sp., Citrus sp., Alstonia congensis, Zingiber officinale, Carica papaya, Staudtia kamerunensis, Mangifera indica, Combretum micranthum, and Cymbopogon citratus due to increased demand during the pandemic. However, Gabon is predominantly covered by forest (over 80%), and most of these species are distributed across all regions of the country (Wakefield Adhya, 2024). This suggests that the overharvesting of these species during the pandemic may not have had a significant impact on their abundance. Nevertheless, it is important to develop conservation planning for species with significant bioactivity. Conservation efforts could include measures such as sustainable harvesting practices and community-based management initiatives to ensure the long-term viability of these species and their ecosystems.

COVID-19 has emerged as the most prolonged and deadly coronavirus outbreak witnessed worldwide in the past 50 years. Despite extensive exploration of various treatments, no definitive solution has been identified, and vaccination efforts have encountered limitations in the face of evolving virus variants. Ethnobotanical surveys conducted worldwide have explored the potential of plants to alleviate COVID-19 symptoms, yielding positive results and encouraging the use of medicinal plants for coronavirus infection management. In Gabon, the country’s relatively low rate of cases and fatalities has been attributed to the consumption of plants traditionally used to treat malaria and flu, both as a preventive measure and in the treatment of COVID-19. Further investigation into the mechanisms of these plants such as anti-inflammatory, antioxidant, antiviral, and immunomodulatory activities is crucial for the development of plant-based medicines that could effectively act during the early stages of SARS-CoV-2 infection. This research holds promise as a significant alternative in the preparation for the inevitable occurrence of future coronavirus epidemics in the coming years. Understanding and harnessing the potential of these medicinal plants may provide valuable tools for mitigating the impact of such outbreaks.