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About this resource
This resource follows the structure and argument of a 2023 integrative review that brings together ethnobotany, botanical identification, constituents, and basic pharmacology of Tabernaemontana sananho Ruiz & Pavon (Apocynaceae). Against a background of use called “forest eye drops” or sananga spreading from villages into cities in Brazil, the authors consider Indigenous medical contexts alongside Western traditional-medicine and pharmacology frameworks.
3 subjects must be distinguished at the outset. The 1st is culturally described use of T. sananho. The 2nd is chemical, cell, and animal research using plant materials such as bark, roots, and leaves, solvent extracts, or isolated alkaloids. The 3rd is the aqueous sananga eye preparation actually placed in the eye. The review relates these subjects but is not a clinical trial administering the 3rd product to people and comparing symptoms or visual function with a control group. It includes no study establishing clinical efficacy of sananga eye drops in humans.
Study design
The authors conducted a qualitative integrative literature review and searched PubMed, LILACS, and the CAPES Periodicals Portal. Search terms included “Tabernaemontana sananho,” “sananga,” “Brazilian Tabernaemontana,” “Tabernaemontana,” and “sikta.” Portuguese-, Spanish-, and English-language materials published through 2022 across a broad date range were considered.
Among 37 records explicitly involving T. sananho—1 in PubMed, 0 in LILACS, and 36 in CAPES—3 papers were selected. To broaden understanding of the plant, the authors also searched for the phylogeny, morphology, and habitat of Apocynaceae, specific indole alkaloids reported for the species, and relevant ethnographic sources. From a total of 421 additional search results, 6 were retained as relevant, and dictionaries, theses, encyclopedias, and books were also used. This was a qualitative integration of different forms of knowledge, not a preregistered systematic review or meta-analysis.
The authors take as an ethical premise that Indigenous views of medicine should not be ranked solely by the measures of Western science and that documenting knowledge is connected to cultural visibility and transmission. This perspective is important to the review’s purpose, but cultural validity and clinical efficacy are not the same determination.
Content
The review describes the classification, distribution, and morphology of T. sananho before tracing regional names and records of use. The plant is distributed from northern South America through the Amazon region; Brazilian records are listed for Acre, Amazonas, Pará, Rondônia, and Roraima. Multiple names—including sikta, abiu bravo, caimo de montaña, airo toañü, and kunakip—are documented, and the parts used and their meanings vary by community.
Cultural-use records cite diverse traditions involving roots, bark, leaves, latex, and other materials. They document knowledge and practices maintained by particular peoples; even when words resembling disease names appear, they do not indicate treatment research using modern diagnostic criteria and a comparison group. In particular, traditions concerning the eye, products sold in cities as “sananga,” and a laboratory methanol extract of leaves are not the same sample.
The phytochemistry section outlines the many monoterpene indole alkaloids reported across the genus Tabernaemontana. Candidates cited for T. sananho include coronaridine, ibogamine, 19-hydroxycoronaridine, 20-hydroxycoronaridine (heyneanine), and voacangine. Isolation of a compound from 1 plant part does not demonstrate that a water-based eye preparation from another part contains the same constituent at the same concentration.
The pharmacology section links reports from isolated constituents, extracts, microbial assays, and animal models with traditions involving nociceptive stimuli, inflammation, microbes, and alertness, discussing a “plausible convergence.” This is hypothesis generation, not proof of effects in humans. The principal anti-inflammatory and antinociceptive experiment described in the review administered a methanol extract of leaves orally to rats; it was not an eye-drop study. Antimicrobial discussion also includes laboratory culture assays, not comparisons of healing in infected people.
Results
The authors’ central conclusion was that several relationships worth investigating can be found between ethnobotanical use records and the plant’s alkaloids and basic research. Animal research involving nociceptive stimuli and inflammation, tests against some microorganisms, and prior reports on indole alkaloids were assembled as candidates for future study.
At the same time, the authors call for additional research on extract properties and rational use of sananga because the plant may contain irritating alkaloids. In particular, the review did not measure whether the liquid used in the eye actually contains irritants, their concentrations or variation, or the ocular-tissue responses they produce.
The “result” of this review is therefore not a clinical finding that eye drops improved visual acuity, infection, eye disease, pain, or another condition. Its contribution is integrating records of traditional knowledge, phytochemical candidates, and findings from different experimental systems while identifying research gaps. No randomized trial, controlled clinical trial, or prospective safety study of sananga eye drops was presented.
Limitations
Only 3 included papers directly addressed T. sananho, and the additional material mixed evidence levels such as books and theses. The design differs from a modern systematic review with a full search strategy, duplicate removal, dual review, bias assessment, and study-level quality ratings. Because heterogeneous materials were integrated, the same term does not necessarily denote the same sample, route, or outcome.
Causal effects cannot be inferred from records of tradition, nor can effects of a finished botanical product be inferred from known activities of compounds. Evidence from another species in the genus, another part of T. sananho, an isolated constituent, an organic-solvent leaf extract, and an aqueous eye preparation cannot be used interchangeably. The review’s “convergence” is the authors’ integrative interpretation, not a quantitatively pooled effect.
Safety
An important warning in the original article concerns possible irritating alkaloids and exposure of ocular mucosa. Even when intense irritation is described as part of a traditional experience, it is not itself an indicator of safety or efficacy. Risk may vary with botanical identity, plant part, concentration, microbial contamination, storage, an individual’s eye disease, and hypersensitivity, but the review established neither product specifications nor a safety range.
Ocular exposure presents safety questions different from oral animal experiments or antimicrobial assays in a culture dish. This resource does not provide instructions for self-use, preparation, amount, or frequency. Nor does it replace diagnosis or treatment when eye abnormalities such as pain, reduced vision, or redness are present.
Source and rights
Original source: Robert AP, Sieben PG, Lima A. Etnobotânica da planta Tabernaemontana sananho Ruiz & Pavon (Apocynaceae) - Revisão Integrativa. Revista Fitos. 2023;17(3):445–459. DOI: 10.32712/2446-4775.2023.1432.
The article PDF and primary journal page at Revista Fitos publish the text under Creative Commons Attribution 4.0 International (CC BY 4.0). This source-aligned resource names the original authors, journal, DOI, and license and restructures the content for English readers. Figures and page images are not reproduced.