The Aristolochia (Aristolochiaceae) genus: therapeutic properties, biological effects and toxicity

The Brazilian flora harbors extensive plant biodiversity with the possibility of therapeutic use. In this context, the genus Aristolochia is widely used in folk medicine. From this perspective, the study aims to demonstrate important characteristics of these vegetables in the current literature. It was observed that the genus has promising medicinal properties that are directly related to its biological and chemical composition. However, it is notable that more research is needed to guide the safe use and encourage the synthesis of new pharmaceutical products derived from these herbs. Studies led to the isolation of 7 lignans, five neolignans, two sesquiterpenes, two diterpenes, eight aristolochic acids and derivatives and three more aristolactams. This study with A. pubescens and Aristolochia lagesian a (-)-cubebin, a dibenzylbutyrolactone type of lignan, is known to reduce larval viability in Anticarsia gemmatalis to give rise to malformed adult insects, it was found that there was an anti-inflammatory activity. -insect pests, in addition to showing anti-inflammatory and analgesic activities. of


Introduction
The World Health Organization (WHO) estimates that about 80% of the rural population in developing countries still enjoy practices related to traditional medicine. That is, they use medicinal plants (Tesser;Sousa & Nascimento, 2018). The medicalization of society is intrinsically linked to normality-pathology thinking, which refers to Western medicine in the 20th century based on scientific ideas. In the USA, medicinal plants were assimilated through chemical syntheses, and a chemical revolution was established. The rescue and appreciation of this practice are essential for current health, notably concerning the Complementary Therapies of the SUS (Corell-Doménech, 2019).
Herbs and their derivatives have accompanied humanity over the centuries, whether for manufacturing inputs, work materials, ornamental, therapeutic, or food use (Almeida Rodrigues et al., 2020). The pharmaceutical industry uses medicinal species to develop commercial products (Brandão et al., 2010). This fact demonstrates how much human beings have always depended on natural resources for survival (Marmitti et al., 2015).
In this context, the monophyletic botanical genus belongs to the Aristolochiaceae Juss family (Piperales). Around 400 plants are distributed in the tropical regions of South America, Asia, and Africa. In the flora of Brazil 2020, the genus Aristolochia is represented by 83 species, highlighting the Atlantic Forest, with 39 species, the Cerrado, with 36 species, and the Amazon, with 35 species. Most are popularly known as "liana-thousand-men" or "jar". Its stems, leaves, and roots are used for stomach ailments, convulsions, gout, asthma, and fever, as they have medicinal properties (Lorenzi & Matos, 2008;Freitas et al., 2020). Different species of this family have different chemical compounds. Some of the therapeutic interests such as terpenoids, alkaloids, flavonoids, lignins, and fatty acids, among others (Navickiene & Lopes, 2001;Pacheco et al., 2009).
These vegetables have phytochemical properties that can benefit pathologies and are used in traditional medicine in countries such as China and India (Latha et al., 2015;Sati et al., 2011).
The widespread use of these plants is based on ethnopharmacological information, and 16 species have documented efficacy (Latha et al., 2015). Among them, Aristolochia is studied for its wide application in folk medicine, anti-inflammatory, and antidiabetic effects, and treating snake bites (Babu et al., 2021); the species Aristolochia albida has anti-malarial activity (Khan et al., 2012). However, some Aristolochia species have proven nephrotoxicities, such as A. fructus, A. gigantea, and A. melastoma (Zhou et al., 2011;Holzbach et al., 2010& Nogueira et al., 2012. Medicinal plants can provide both therapeutic and toxic, and even lethal effects that are linked to their phytochemical compounds, which is why they must be subjected to toxicological tests, including genotoxicity and cytotoxicity (Badrie & Schauss, 2010). Although scientific knowledge about the species of the genus Aristolochia is still scarce, it is known that many are native to Brazilian biomes and have promising ethnopharmacological potential, which makes them a target for further studies aimed at elucidating their toxicological potential and pharmacological effects.
In this way, safe use through investigation of the toxicity of Aristolochia and further studies related to their bioactivities and respective therapeutic effects are of utmost importance. In this context, this study addresses the phytochemical and ethnopharmacological characteristics, medicinal properties, and toxicity of the genus Aristolochia found in the literature.

Methodology
For the elaboration of this study, exploratory research of a qualitative narrative nature was carried out, built from the search in the following databases: Latin American and Caribbean Literature on Health Sciences (LILACS), Scientific Electronic Library Online (Scielo), and Sistema Online Search and Analysis of Medical Literature (MEDLINE/PUBMED).
The descriptors were crossed using the Boolean operator "and" as follows: Aristolochia AND Ethnopharmacology AND Phytochemistry AND Bioactivities AND Therapeutic properties. The guiding research question of the study was: What are the phytochemical, ethnopharmacological, therapeutic properties, and toxicity of the genus Aristolochia?
The inclusion criteria were studies available online, with free access, full text in English, Portuguese and Spanish, published between 2005 to 2021, related to the proposed theme, and answered the guiding question. Theses, dissertations, congress abstracts, proceedings, incomplete articles, duplicate articles, and articles not available in full were excluded.

Results and Discussion
The search in the databases resulted in 129 articles, of which 38 were excluded because they were not published in the defined period, and 91 articles were selected. Of these, 63 were chosen by reading the title, excluding articles not available in full and with other methodologies. Forty-two were selected by reading the abstract, of which 07 were excluded because they were duplicates, 35 of which were read in full and included in this review.
It was possible to observe that the scientific community has used Aristolochia spp. to unveil some of its pharmacological and therapeutic properties. In this sense, different secondary metabolites with biological effects are described, and such information is listed in Frame 1. Machado et al, 2005.

Aristolochia ridicula
Flavonoids, dimers of chalcones, and flavones, as well as biflavones, were isolated. The studies are: two new biflavones (ridiculuflavone A and B); a new chalconeflavone tetramer (ridiculuflavonylchalcone A); a wellknown cyclitol (proto-quercitol). Concerning biological activity, they are used in traditional Brazilian medicine for stomach problems, anti-inflammatory, antiasthmatic, as well as androphilic and anticarcinogenic.
Stems and leaves. The preparation of the extract of the leaves had ethyl acetate as solvent.
It contains benzylisoquinoline bialkaloids, biflavonoids and 11 tetraflavonoids have been described, 10 of which were isolated from Angiosperms: three from A. ridicula. As its biological activity has been used mainly in traditional culture as abortifacients, for stomach treatments, androphilic, antiasthmatic, expectorant, and also recently, in weight loss therapies without differentiation between them.
Sheets. Extraction with hexane and ethanol, fractionation with shepadex for compound isolation. Wang et al, 2018.

Aristolochia manshuriensis
The stem is used in traditional Chinese medicines for anti-inflammatory, analgesic, antitussive, antiobesity, antibacterial, and antiasthmatic. Studies led to the isolation of 7 lignans, five neolignans, two sesquiterpenes, two diterpenes, eight aristolochic acids and derivatives and three more aristolactams. This study with A. pubescens and Aristolochia lagesiana (-)-cubebin, a dibenzylbutyrolactone type of lignan, is known to reduce larval viability in Anticarsia gemmatalis to give rise to malformed adult insects, it was found that there was an anti-inflammatory activity. -insect pests, in addition to showing anti-inflammatory and analgesic activities.
Tubers and roots. Ethanol extract and acetone extract. Zhai et al, 2005.
One hundred seventeen compounds and their analogs were isolated from a methanolic extract of A. arcuata root.

Sreeharsha et al, 2021. Aristolochia bracteolata
We analyzed the antimicrobial activity and cytotoxicity of silver nanoparticles biologically synthesized from the leaf extract of Aristolochia bracteolata against the A549 cancer cell line. The silver nanoparticle showed better antimicrobial activity when compared to the crude plant extract. Satisfactory cytotoxic effects by nanoparticles derived from plant extract against the A549 cell line, followed by the potential of biologically synthesized silver nanoparticles, can be considered a finding in treating human laryngeal carcinoma and can be categorized as a potent anticancer agent.
Fresh leaves. Extraction with ethyl acetate, methanol, and ethanol until the solvent becomes colorless, then rotoevaporated and resuspended with a specific solvent.

Bolla et al, 2019.
Aristolochia saccata Investigating the healing ability of Aristolochia saccata leaf extract using the experimental "scratch assay" model as the primary model, L929, a human fibroblast cell line, was used. The MTT assay revealed that the extract had no cytotoxic effect on the cells and, at a higher concentration, showed mild toxicity against scraping, showing 34.05%, 70.00%, 93.52% wound closure at 12 hours, 24 hours, and 48 hours of incubation, respectively. Cytometry revealed that the expression of collagen-1 MEC remodeling factor was induced.

Bourhia et al, 2019.
Aristolochia baetica Qualitative and quantitative analyzes of the roots showed the presence of polyphenols, tannins, alkaloids, flavonoids, and saponins. Acute toxicity was assessed in mice by gavaging single doses of 1, 2, and 4 g/kg body weight for 14 days; subacute toxicity was done using repeated doses of 1, 1.5, and 2 g/kg/day for 28 days. Acute toxicity does not show mortality and signs of toxicity in the groups treated with 1 and 2 g/kg. The mortality rate was estimated to be 16% in the group treated with 4 g/kg. Subacute toxicity showed changes in serum parameters at doses of 1.5 and 2 g/kg/day. Histological changes were at the highest dose of 2 g/kg/day. There was toxicity at repeated doses, but no toxic effects were observed with a single dose below 4g/kg.

Bourhia et al, 2019.
Aristolochia baetica Aristolochia paucinervis Antioxidant activity (by DPPH assay), antiproliferative activity on human cancer cell lines (T-24, HT-29, and Hep G-2), and acute toxicity. The two plants have different classes of metabolites, and total polyphenol Roots. Soxhlet extraction at 40°C for 2h using methanol as solvent.
concentrations are expressed in higher concentrations in A. paucinervis. DPPH activity with IC50 values of 150 ± 8 μg/ml and 160 ± 10 μg/ml, respectively. Both species have antiproliferative effects on all cancer cell lines tested. Regarding acute toxicity, no signs of toxicity or mortality were observed in mice treated orally with 2000 mg/kg.

Omari et al, 2019
Aristolochia longa Antioxidant activity (by the DPPH assay) is widely used in Moroccan medicine. Many healers also use a small amount of the rhizome powder with honey or salted butter to treat abdominal pain and upper respiratory tract infections.
Roots. High temperature with solvents of different polarities under magnetic stirring, filtered, and rotaevaporated.

Ahmad et al, 2021
Aristolochia ringes Extracting antihyperglycemic activity on alpha-amylase and alpha-glucosidase activity was compared with the standard drug (acarbose). Inhibition in each case was dose-dependent for extracts and acarbose at all investigated dose levels. By assays, the highest percentage of inhibition occurred at the highest concentration for extract and acarbose with no corresponding significant difference.
Aristolochia contorta Twelve compounds, including two new aristolochic acid analogs with a formyloxy and 10 known derivatives of aristolochic acid. Their structures were elucidated using extensive spectroscopic methods. Its cytotoxic activity on human HK-2 proximal tubular cells was evaluated by the MTT method. Among these molecules, compounds 3 and 9 were shown to be cytotoxic.

Roots.
Source: Authors. known that free radicals are protagonists in the progress of diseases such as cancer and some of the immune system. And in this context, drugs with antioxidant properties are essential to prevent and treat conditions originating from oxidative stress (Asimi et al., 2013;Devasagayam et al., 2004).
In this same scenario, it was observed that some Aristolochia have the antihyperglycemic capacity, which is significant bioactivity because currently, in medicine, the drugs used in the treatment of diabetes have several side effects. And therefore, plants that can offer new alternatives to revolutionize the antidiabetic drug market with safer products and economic viability are estimable (Marles & Farnsworth, 1994).
The ability to be involved in the healing processes of some species of the Aristolochia species also drew attention in this narrative research, as it identified bioactive compounds from extracts of medicinal plants to search for new therapeutic agents with different mechanisms of action to act in wound repair. It is highly reasonable since the skin, besides being the largest organ of the human body, has a protective function. And the wound healing process is mandatory to maintain lost tissue homeostasis (Bolla et al., 2019). The anti-inflammatory potential of some species of this genus was also evidenced, corroborating the practical use reports (Battu et al., 2011).
The evaluated works suggest that representatives of the genus Aristolochia are widely used in traditional medicine in our country and around the world, depending on the geographic distribution of the species. Figure 1 represents some species of the genus Aristolochia. In addition, herbs of this genus have essential biological effects, such as antidote to snakebite, anti-inflammatory, antiasthmatic, antiproliferative, and abortifacient potential . In such a way, they are rich in compounds of therapeutic interest, which are being, little by little, elucidated by the scientific community. However, it is necessary to investigate the true medicinal potential, especially concerning its toxicity profile. Despite the therapeutic reports, harmful effects have already been described and reported for plants of this genus acting as a nephrotoxic, antispermatogenic, and antifertility agent (Dey & De, 2011), in addition to demonstrating toxicity and cytotoxicity in bioassays (Silva et al., 2019).

Final Considerations
The use of medicinal plants is a practice that has been around humanity over the centuries, through the manufacture of inputs, work materials, ornamental, therapeutic, and food use, among other purposes. Currently, the pharmaceutical industry uses several medicinal species to synthesize new commercial products. This demonstrates how much human beings have depended on natural resources for survival.
Aristolochies are traditionally used in folk medicine and have numerous pharmacological properties of therapeutic interest, as described in recent research. Thus, although understanding the genus is related to its ethnopharmacological potential, there is essential knowledge to be investigated to understand its true medicinal potential, especially regarding its toxicological profile and, consequently, predictions of safe use.